Outsorcing

Nowadays, many companies use outsourcing to be an alternative source to do specific work, processes, and activities to get benefits from within an organization to outside providers without aware of effects on local worker or country economic. According to Reap W. (2012), some companies in United States and other area make a lot of profits from outsourcing in term of economy and businesses such as production of material product while others are suffer from transferring outsourcing job to other countries that impact on United States economic.Companies should once about local workers more than self-benefit because if they continue to destroy local Job that will cause major problem to society. According to wry. Serviette. Com, what is outsourcing (n. D. ), outsourcing is a process of hiring outside internal companies or workers from domestic or abroad to do specific work such as manufacturer, marketing or even content writing. Presently, outsourcing is very popular in slow develop countr ies such as Laos, Vietnamese, India and Thailand because several factors.According to Overly (2007), low costing, lack of n-house resource, variable capacity, access to specific IT skills, increase flexibility to meet new business and commercial conditions , these are the major factors that lead big country come to invest outsource in undeveloped country. For example, according to Matthews (2012), many U. S companies invested in India and Vietnam such as Aids, Leno. These companies mainly produce their product oversea because lower labor cost that make them produce product in cheaper price and customer can afford it.Another example is gasoline, gasoline price is continue decrease, even Hough much oil are produce from other countries so public was stated that the factor effect to gas prices are more money spend needs and other wants. According to Plunked research, â€Å"Introduction of outsourcing and offshore industry', one of outsource service very popular and continue to be stron g hiring thousands of Jobs to work in China and India is engineer and researcher that in 2010, the number of worker in IBM is from oversea is over 80000 people and it reached to 112000 people in 2012.These examples were connected to the reasons of manufactured goods and sots, materials and services. Outsourcing causes local worker who live or work in developed country lose their Job. According to Mapping (2008), outsourcing purpose is to cut production cost by hire other foreign companies and workers to do specific work so it leads to people losing Job and 40 percent of US company is sending Job to foreign countries and over 31 percent of US citizen are lose their Job. This statistic seems obvious that outsourcing make US citizen loses their Job and it can connect to major problem.For example, according to kimono (2009), an increase of trade U. S. Jobs to oversea as well as increase of Jobs losses that has impact on U. S. Economy as a whole such as MM, Ford Motor and GE Capital have sent a high number of Jobs to other countries and chosen employ cheap labor instead of hiring worker in their country. According to the article â€Å"what is outsourcing†, one of the major factors companies choose outsourcing is cost of outsourcing that can reduce amount of money by outsourcing some of the Jobs and tasks such as content creation and server monitoring and management.According to Alex (201 1), a research shows the estimate number of outsource in 201 5 is 3. Millions Job send to oversea as a result thousand of U. S Jobs will be lost each year and it leads to be shutdown country economic and that layoff can cause stress on human mind and lives. For example, some common depression symptoms are feelings of worthlessness, helplessness, guilt, fatigue, insomnia and restlessness, according to Empower. Some symptoms of anxiety include worrying, obsessive thoughts, fear, panic, impatience, concentration problems, rapid or irregular heartbeat and nausea.Moreover, outsou rcing can make many Jobs at risk to distinct, according to Opposing viewpoint â€Å"Legislation to Limit Outsourcing Is Essential and Effective†, The Bureau of Labor Statistics shows that about 51 5 occupations are at risk to distinct and 160 of these Job are change to be offshore outsource and over 300,000 occupations will disappear annual after year 2015. These reasons have showed that outsourcing causes Job losing, slow development and mental illness on people. Moreover, outsourcing causes global economic crisis which is major problem to every country because it can affect to world economic.According to Rather (2014), who has a PhD in organic chemistry from Oxford University as well as a Bachelor of Technology n chemical, In 2013, the number of unemployment is increased millions people that causes global economic crisis, in contrasted, India, a country which education has just boomed, there are now has fewer people unemployment than U. S. ‘s. According to Losing Jobs , The real impact of the Economic Crisis (2012), â€Å"As more and more businesses go to the wall, rising unemployment levels are a clear and devastating indication of the problems that workers are facing worldwide.The International Labor Organization is forecasting that more than 50 million workers could lose their bobs this year and up to 200 million more will be plunged into extreme poverty. The Organization for Economic Cooperation and Development says that by next year jobless numbers in rich nations could rise by eight million to 42 million. The UK has just registered the biggest quarterly Jump in unemployment since the 1981 depths of recession. † This is a result from outsourcing that lead to local worker in U.S loses their Job and it may lead to major problems. For example, according to Junker (n. D. ), investment in real capital cities is stagnant and a lot of consumers have slowed Roth in paying money and it make economic crisis. These factors are connected to slowe r develop country and if this continue to long-term protesting will happen in finally. On the other hand, outsourcing can improve country economy and develop country standard. According to Grant G. (n. D. ), outsourcing can offer over 90000 Jobs to local worker and foreign worker in 2003 that U.S. Companies use offshore sourcing lower costs, to allow them to hired U. S. By called for a tax credit to help pay extra money for American companies which agreed to stop hiring worker overseas operations to take umber of Jobs back to American land as part of his â€Å"incurring† agenda. Surprisingly, more than 100,000 IT Job software and hardware are moved to other countries , but the number of U. S. Job is created more than 90000 as the result from cost saving and offshore outsource. However, outsourcing can destroy country economy and overview of country.For example, outsourcing causes major problem by job losing when people lose Job, they will concern their money how to live, how to spend their money as the result they will spend money less and country economic will struggle then country will slower developed. Moreover, when people get more stress and it over limited that person can cope with, they will suicide and this problem will bring overview of country get worse so these can demonstrate that outsourcing can cause many problem that a problem connected to other and it will be major issue.In sum, U. S. Companies and government should cooperate to reduce number of using outsource to solve the following problems that will happen after offshore order to relief economic crisis and decrease number of unemployment that caused by outsourcing.

Helping Make Hair Loss History Essay

Define Propecia’s potential customer base. What is Propecia competing against in the consumer’s mind? What can be learned from Rogaine’s experience in the marketplace? Propecia is a drug against hair loss, effective both on stopping and reversing the Male Pattern Hair Loss. According to Tom Casola, the brand manager of Propecia, the potential customer base is at least half of the male population, as MPHL occured in 30-40 million American men, which is around 50% od Caucasian men under the age of 50, with the lifetime incidence to reach 100%. But when compared to others race and nationalities. Neither black men, Japanese men nor Chinese men were as likely to develop MPHL as frequantly as Caucasian men, at least not until later ages. What Propecia is competing against in consumer’s mind is that, according to the research Merck did, consumers believe hair loss to be a slow process and they do not seek treatment early enough, at least not before trying a couple remedies of their own including brushing, wearinh hats, combing the hari over bold spots, which is mainly because they are not fully aware of the degree of their hair loss, as it is most likeley happening at the back or top of their head. Although 2/3 of men losing hair consider of it to be a problem, half of those consider it to be a futre problem, and the remaining 1/3 does not even consider it to be a problem. The consideration of this problem to be a future problem, or an inevitable problem, builds kind of a resistance in terms of the willingness to fight it. And Merck needs to focus on showing that it is a current problem and not a future problem and shoudl be addressed as soon as possible, in order to have success over it, and making it not inevitable. Rogaine, a topical including minoxidil, affective against hair loss, as long as used, was the frst FDA approved topical hair loss intervention, which was not successful as a prescribed medicine despite the belief of its potential success in revenue, until it became an on-the-counter product. What Propecia can learn from Rogaine is that, the product should be very careful with the creation of consumer expectations, because if it fails to keep up to those expectations, it can end up like the first launch experience of Rogaine, not coming even close to the expected revenue levels. Although it would not be easy to set the right level of consumer expectation, lowering expectations should be blaned with also creating a positive hop efor the product in the eyes of consumers. 2. How does a customer come to use Propecia? How can Merck best influence that process? Because hair loss is not conceived by physicians to be an urgernt problem, consumers should be directed in terms of marketing in order for them to use Propecia. As mentioned earlier, hair loss is a common problem for most of the men and a remedy is needed not because it is an urgent or a fatal problem but for improving the lives of those people, which is one of the objectives of Merck. According to past experience of Merch with other products, especially those it advertised through direct-to-consumer advertising, which it plans to do for propecia, consumers who asked their physician for an advertised drug, receieved a presciription for it (75%-85% of the the patients). 3. What type of ads, if any, should Tom Casola run at product launch? What message should Propecia convey to potential customers? It is a pretty tough decision to make, choosing one of the three add types. Help Seeking ads would have a negative affect mostly because the ads should be brandless, but the launch is at similar times with the extra strength formula Rogain’s launch time, and as the brand awareness of Rogaine is high, our ads would benefit them more than it would Propecia. On the other hand, product claim ads, although seems like a sound decision to go with, has a high potential risk, becase the side affects are to be mentioned in the ad, and creation of a brand awareness assosicated with seemingly high risks of sexual side effects for men and pregnancy problems for women, it would not be a good timing for highlingting these side effects, where the competition is coming with a more effective product compared to the strong product already dominating the market at some level, with not necessarily this kind of serious side effects, although they are not high risks. Third option of reminder ads, which do not seem to be the best strategy at any other given time, as mentioned by Casola, there is no point in having an ad that creates brand awareness where you cannot even tell that the product is an hair loss product, at this time it seems like the soundest road to take. There is a risk that the brand awareness would be empty inside, but along with working with doctors, mostly dematologists who would be more eager to prescribe Propecia, and urging people to see a dermatologists in the ads, would be the best of the options. This way, making the problem a health issue, which should be handled through a dematologists would create some sort of barriers for the on-the-counter competition especially the new Rogaine to come. 4. What role does a physician play in this context? How much detailing effort is necessary? Pysicians are primarly the customers of prescribed drugs, as they are the ones prescribing the drugs to the patients, the realt consumers. In order for the making the pysicians to prescribe the intended drugs, pharmaceutical companies have sales representatives, who directly go to the physicians and describe the drug, which is called detailing. According to the data given in the case, the potential face-to-face interaction between a sales representative and a physician is about 2 minutes, where the sales representative is supposed to do detailing of 3 drugs. In order to have an effective detailing to persuade pysicians to proescribe the intended drug almost 6 visits on average paid to the pysician. 5. Do you think a first year sales forecast of $60 million would be conservative or optimistic? First of all we need to consider that the potential hair loss markets accounts for about $1. 5 billion of annual sales. Half of the market is hair loss surgery and the rest is divided between mechanical and topical solutions. In order to forecast a $60 million sales a year, Propecia needs 100. 000 customers who spent $50 per month. When we compare this to the unsuccessful lounge of Rogaine, as a prescribed drug, costing $60 per month, it created 400. 000 customers and generated $100 million sales. So compared to this with the knowledge that being scientifically proven- at least among a majority of the clinical trials- and having a better success potential than Rogaine, even on the eve of Rogaine more effective product coming, it is conservative to think Propecia would reach $60 million sales forecast for the first year.

Cellular Reproduction Essay Example | Topics and Well Written Essays - 500 words

Cellular Reproduction - Essay Example They divide constantly and with rapid pace without exhibiting any contact inhibition. As the data suggests, cancer cells outnumber normal cells at the later stages of cell division, indicating that cancer cells divide at the swift rate and complete their cell division faster than the normal cells. Normal cells follow the regulated time interval for cell division or reproduction with balanced signaling pathways while cancer cells do not reveal any kind of signal transduction. Moreover, cancer cells are capable of angiogenesis enabling capillary formation from a nearby blood vessel so as to feed the growing tumor cells. Normal cells cease their cell division after a certain time while the cancer cells proliferate in any order violating the rules of cell division. Although normal cells taken from different tissues as in the present case display different morphology but the cancer cells taken from different tissues do not flaunt their distinct tissue morphology as there is a loss of spec ialized function. The elevated rate of cellular division ceases them to execute their specialized function (Ginger) 2. Which type of cancer shows the most aggressive growth? Explain.

Visual Analysis of Edgar Degas Art Work Essay Example | Topics and Well Written Essays - 750 words

Visual Analysis of Edgar Degas Art Work - Essay Example However, in a social setting, it is normal for low achievers and those who do not shine in every undertaking especially in music to experience stress, which is evident from a lone dancer leaning on the wall on her forehead. This action usually actualizes the Degas portrait, thus implying that it is real and not a product of imagination or illusion. Beside the master, there is a watering can (for watering the floor to maintain its quality), violin bag and hat holding the tutoring notes pamphlet. Degas has immensely and skillfully utilized color where in this portrait they are white and black coupled with varied shades. White is evident in the color of the dancers’ clothes and the pamphlet where they have blended to bring out the contrast amid the environment and the perfumers (since black and white complementary). Besides, the artist has diversely illuminated the entire portrait where more intensity is in the forefront contrary to the back. It seems the light emanates from the front where the artist takes the entire scene (The Metropolitan Museum of Art). Conversely, there is a ray entering in the dancehall from the back slightly opened the door, but it is not powerful enough to cast an illumination on the floor. There are no organic shapes except regular, which are evident in various objects across the dancehall. For illustration, the oval-topped mirror, rectangular shapes (door and bottom of the mirror) and circular master’s hat. Light has induced aspects of value via varying shades from the front to back. This has created depth, which is evident in the portrait and whose extension starts from the front towards the back. The portrait is asymmetrical since its activities seem to dominate the left side, but it depicts unity where the dispersion of the dancers yields to the utilization of the entire room. The portrait is a public image regarding meticulous process,

An Analysis of the Common Theme of Physical Violence in A Short Essay

An Analysis of the Common Theme of Physical Violence in A Short Account of the Destruction of the Indies and Titus Andronicus - Essay Example "A Short Account of the Destruction of the Indies" depicts colonization and Europeanization of the American Indians by Spaniards. Euroamerican settlement of the West accelerated, the government abandoned gradualism in favor of comprehensive programs for assimilation. The savage, noble or ignoble, was judged capable of civilization. Those who embraced it would be welcomed into mainstream society. Those who balked would nevertheless be compelled to behave. In a short time, no more than a generation, the old ways would die out. The savage would disappear with the passing of the frontier. Instead of a geographical expression, the West became, in the imaginations of Americans stranded in the cities and towns, a wild region inhabited by even wilder humans, some white and brown, but most red. Casas depicts: "Guacanagari himself died up in the mountains, broken and destitute, after he had fled to escape the massacres and the cruelty inflicted by the Spaniards, and all the other local leaders who owed allegiance to Guacanagar perished " (20). The kind of historical criticism which has laid itself most open to attack has based its conclusions on limited data and unwarranted assumptions; thus it has been essentially unhistorical. Shakespeare He shapes the character of Aaron as an independent force of evil, rather than as a mere agent of the queen. He introduces the parallel with Ovid's tale of Philomela, and he adds the final triumph of justice and order with the return of Lucius to Rome, in spite of the inconsistency which this involves, for there is no reason for a Goth army to serve Lucius against their own queen. Shakespeare also makes of Marcus a virtual chorus to comment upon the action as the play unfolds. His most important innovation is in his conception of the principal characters and their relations to one another. Titus Andronicus is a commanding figure. He is a great and initially virtuous man, the first of Shakespeare's heroic figures whose very virtues are the source of their sins. In many ways he is a forerunner of Coriolanus. Titus embodies all the ancient Roman virtues: 'A nobler man, a braver warrior, / Lives not this day within the city walls' (I.i.25-26). He has given his life and his so ns unselfishly in the cause of his country. He might now be emperor, but he respects hereditary right and chooses Satuminus instead. He is stern and he is proud, the master of his family, the last of the ancient Romans. In contrast to heroes themes presented by Shakespeare, A Short Account of the Destruction of the Indies creates a negative image of the Spanish colonizers and cruelties committed by them against peaceful population. In their thoughts about the West and its original populations, Spanish colonizers variously imagined an Indian to be a noble savage, a rapacious killer, a reservation idler, the vanishing American, or a war-bonneted equestrian raider of the plains. The last image proved to be the most persuasive and, given Indian portrayals in motion pictures and television

Tinas Restaurant Case Study Example | Topics and Well Written Essays - 750 words

Tinas Restaurant - Case Study Example There exist a higher number of potential customers. The region also has a higher level of income with are being segmented to give room for her to issue variety while offering services. The diverse nature of Hamilton road in the city of London provides him with the opportunities to offer customers with a wide range of products. The threats come from his potential competitors who include Montana’s Cookhouse, Kelsey’s, and Boston Pizz. The other threat is the unpredictable nature of the customers with trends changing on consumer preference. As a new business Tina faces an uphill task in ensuring that she penetrates the market. The loyalty of customer in London city may make her face challenges while marketing the products to customers. Lack of a viable plan may affect Tina’s effort of penetrating the market and offering her customers better services than her potential competitors. The major competitors of Tina are including Montana’s Cookhouse, Kelsey’s, and Boston Pizz. Montana cookhouse owned by Cara operations Limited, provides the greatest competition to Tins. They boost of two products include the smokehouse rib and fresh Canadian AAA steaks. The restaurant is located in Hyde Park. It boost of 700 branches across Canada. The restaurant sales are estimated to be over $1m for the single unite and a system wide sale of $1.5 billion. They utilize their official website to market their products. The billboards are the other avenues the company has focused on in selling their products to the market. Among their services include customized services for the customers. They offer variety in their products. The other competitor in the line of business is the Boston Pizza. It is located north west of London town. They share a geographical location with Montana’s Cookhouse. Boston Pizza also boasts of a large market share with over 350 branches of the same restaurant across the country.

The Roman Fever Essay Example | Topics and Well Written Essays - 1000 words

The Roman Fever - Essay Example Background Essentially, the story was about the friendship of two women, Grace Ansley and Alida Slade. They were vacationing in Rome with their daughters, Barbara Ansley and Jenny Slade. This was the second time that the two elderly women had been to the city. They had previously visited Rome and the present travel provided a conducive for the two protagonists to reflect on their lives. A good part of it came as offshoot of what transpired in Rome many years ago. As they looked back on the past, a secret was revealed by Mrs. Slade amidst the long rivalry that hounded their friendship through the years. There was some sort of love triangle between Grace, Alida and her husband Delphin Slade in the past. It turned out that Mrs. Slade wrote a fake letter to Mrs. Ansley that supposedly came from Delphin Slade. The letter invited Grace to a tryst in the Coliseum in an effort to break her heart and cease getting in the way between Alida and Delphin as a consequence. It turned out that the t ryst actually transpired with Grace and Delphin meeting each other after the former revealed that she answered the letter and Delphin actually came. Strong Competing Women The story was a convoluted affair, but typical of the experience of the women of the American upper class during the 1930s. What makes this theme remarkable is that the story was controlled throughout by female protagonists, which depicted strong female roles. Certainly, the story was dominated by the two women and, then, there were their daughters, playing minor parts. The only physically present male in the narrative was the Italian waiter and some unseen Italian suitors who, from the statements of the protagonists, can be considered as objects of the predatory desires of their children. When the husbands were finally mentioned, they were referred to in passive roles or as tools in making a make a point, introducing an argument, and issue or a narration of experience. Mr. Horace Ansley was brought up by the two women only to be referred to as dull, spineless, boring and insufferably passive character – â€Å"just a duplicate of his wife† (12). It was obvious that his wife dominated him throughout their married life. Meanwhile, Delphin Slade was only introduced when the letter was brought up. Here, he was a facilitator or a device, if you may, in order for the desired reaction in the case of the letter to be effective. They are not unlike the Italian lovers previously mentioned. They were objects of the female rivalry and female negotiations as they navigated their relationships and pursued their objectives. They were there for a reason and such reason was determined by the women who need their respective resources and ammunition to outdo each other. There are some subtle hints provided by Wharton to support the above point of view. Delphin closely resembles the word "delphic" which is synonymous to ambiguousness and obscurity. The name Delphin may also be related to the Roman Apollo, who was the god of light and represents manly beauty. So Delphin was like the trophy - the object - by which Grace and Alida and their mothers, before them, worked hard to achieve. From the very first words of the story, this tone was already established: â€Å"the women, ladies of ripe but well-cared for middle age moved across the lofty terrace of the Roman restaurant... looked first at each other, and then down on the outspread glories of the Palatine... with the same expression of vague but

Reading Response #3 Essay Example | Topics and Well Written Essays - 1250 words

Reading Response #3 - Essay Example the article describes, about how the class room atmosphere or its appearance imposes an impact on the teachers, children and education system of the school and the process through which it develops the structure of the education and intellectual capabilities of the children in the later stages of their life. Secondly, it further discusses about the critical aspects of school environment by analyzing different kinds of methods such as Macro Analysis, school appearances and classroom analysis among others. Thirdly, the article portrays the expectations and influence of the kindergarten teachers about the chances of the success and failure of the children within the available education environment. The final and the fourth stage reflect on the fact that the article expresses the thought of equal distribution and educational opportunity among the children. The author plans to observe the poor children in formal and informal ways as well as record their activity and development within the school and clarify the benefits that have been derived from the analysis. The article provides the information regarding the process of that the school environment follows in terms of the teacher’s involvement and expectation, which influenced and benefited for increasing a diverse view towards the future development of the children. In the provided article, the author discussed about the distribution of Socio-Economic Status of the children in the kindergarten school. He divided the family based on the number of the children who were associated with the school. Following the segregations the author classified those selected in 3 tables that are designed based on the sitting arrangement specified for the children. The children who are the only child of the parents have been depicted under Table-1. The depiction under Table 1 is reflects on the fact that the lifestyle followed by the people is more sophisticated and quite different from the other people who are listed under Table-2

The report about new business plan-KFC Essay Example | Topics and Well Written Essays - 2000 words

The report about new business plan-KFC - Essay Example However clinching fact would be the expected enthusiastic response from target population of locals, students and visitors of Aberystwyth town. Typically, an established brand name's franchise business would be less risky than other new ventures because the business idea has been tested and the KFC products enjoy global acceptance and saleability. Studies have reported that franchises are safer than other capital deployments in businesses with a failure rate of less than 5 percent rate compared to 90 percent failure rate for some independently initiated restaurants. Banks are also more liberal in extending finance to a franchising business, given above facts, and can finance up to 70 percent of the initial capital costs. Taking up a small business model franchisee of KFC appears to be a challenging, profitable and safe business opportunity. In the following paragraphs a business plan is taken up to commence this business systematically. We believe we have a good head start in Aberystwyth Market as there are just three competitors in fast foods and we will be specializing in chicken products which enjoy global acceptance and popularity. ... 1.3 Founder of the creation of Kentucky Fried Chicken & History /KFC Brief BackgroundKFC operates in 74 countries and territories throughout the world under the name "Kentucky Fried Chicken" and/or "KFC." It was founded in Corbin, Kentucky by Colonel Harland D. Sanders, an early developer of the quick service food business and a pioneer of the restaurant franchise concept. For the Colonel, perfection was the only acceptable level of performance for a KFC restaurant. This perfection was extended to both "finger lickin' good" food and warm, friendly hospitality. These same standards continue today with our goal of excellence for every eating experience in KFC restaurants. In the beginning of KFC, there was nothing-save a chicken recipe and a promise. "The recipe was, of course, Harland Sanders' special blend of eleven herbs and spices cooked in his own secret way. There was no striped red building, no cardboard bucket with the illustrated icon known as "the Colonel." There was no fiber glass replica of the diminutive and rotund man standing in the corner in a string tie"(Howell,2000). Sanders' signed up his first franchisee in 1952. KFC changed management several times and was under John Y. Brown and Jack Massey, Heublein and R. J. Reynolds. By the time KFC was acquired by PepsiCo in 1986, it had grown to approximately 6,600 units in 55 countries and territories. Now it is under Tricon.It is important to observe that despite frequent management turnover the KFC continued to have very detailed and effective franchisee agreement which allowed substantial leverages to franchisee units to improve the group working by their innovative methods. This unit would like to attempt the same by taking special initiatives in use of technology and dcor as

The ghost of Christmas Essay Example for Free

The ghost of Christmas Essay Scrooge! A squeezing, wrenching, grasping, scraping, clutching covetous old sinner! Hard and sharp as a flint , from which no steel had ever struck out generous fire ; secret and self contained , and solitary as an oyster Charles Dickens coveys his moral message in a christmas carol by raising awareness of the poor and peoples perceptions of the poor in the Victorian times. Most of his literary works concerned the poor and how they lived. Another of his famous novels was Oliver Twist about an orphaned boy. He wrote about this issue because he had experienced abject poverty himself. When he was only nine, his father, mother, and his seven brothers and sisters were sent to debtors prison. This left Dickens out in the cold as a child labourer. After his family were released, Charles Dickens was fortunate enough to go back into education and became a law clerk. He then wrote these novels to describe the desperate poverty in society and raise peoples awareness. Throughout his life, Charles Dickens was a philanthropist, doing many good deeds for his community. He was going to bring the poverty issue to the attention of his readers by producing a campaign leaflet but then realised that more people could relate to a story and more people would read what he has to say. A christmas carol is an allegory. He is saying that people, who live a greedy senseless life, will suffer themselves in the future. If we live our life doing good deeds and generally getting into the spirit of seasons then we will be rewarded in life and the after life. The main character in a christmas carol is Scrooge. At the start of the story, he is described as a covetous old sinner and his famous words bah, humbug! describes his opinion of Christmas. In his school days, he was very serious and was more interested in his education than Christmas. Later in his life he had a fianci e and he used to enjoy the festivities. Money then took over his life and he has rejected everyone ever since and because of this, even though he is financially richer, his life is much poorer. Scrooge, throughout the story, is visited by three ghosts. One of the christmas past , one of the christmas present and one of the christmas yet to come. The ghost of the Christmas past represents his memory and makes Scrooge reminisce about his life as a child and what Christmas was like for him then. The school is not quite deserted, a solitary child, neglected by his friends, is left there still This child, of course is Scrooge. He cared more about his education than Christmas. His friends, if he had any, had left him to look a sad sight on his own. This image made Scrooge think about what he had missed out on in his childhood. He had rejected the opportunity for fun or any friends and he felt bad about it. Even having thinking this through, he still needed more evidence for him to change his frame of mind. The next ghost to visit the misguided Scrooge was the ghost of the Christmas present. This ghost represented charity and showed Scrooge how giving to other people can be a fun part of Christmas. He took Scrooge to various parties which included his old employers party, Fezziwig, his nephews party, Fred , and the Christmas dinner of Bob Cratchit and his family, who, in the sense of that time, were very poor because of the ridiculous wages given by Scrooge in his office. At his nephews party, they were playing a game of yes and no where they ridiculed Scrooge; the brisk fire of questioning to which Fred was exposed, elicited from him that he was thinking of and animal, a live animal, rather a disagreeable animal, a savage animal, an animal that growled and grunted sometimes and talked sometimes.. What is it? Cried Fred. Its your Uncle Scrooge!!!!! This made Scrooge feel very upset inside that his nephew thought of him this way. At Bob Cratchits house, Bob proposed a toast to Scrooge and his wife was very reluctant to do it. He also saw Tiny Tim, Bob Cratchits son, who was very ill and as the family was so poor, they could not afford to help him. This also made Scrooge hurt inside and for the first time, Scrooge decided to change his ways. The ghost of Christmas present shows Scrooge how to celebrate Christmas , but he still needed a small amount of help, and thats where the ghost of Christmas yet to come came in. The ghost of Christmas future was in the shape of the grim reaper and the ghost that Scrooge feared the most. He represents death and Scrooges fear of it. He shows Scrooge what impact his death has on the community. They are celebrating. This scares Scrooge as he didnt realise how much people hated him. Spirit, he said, this is a fearful place. In leaving it, I shall not leave its lesson trust me, let us go! Undoubtedly, the turning point for Scrooge though, was when he saw the empty chair and crutch that was once Tiny Tims. The Cratchits could not afford to help him so they were mourning him. This brought tears to Scrooges eyes. He knew that he could do something to help. What of Tiny Tim? The ghost doesnt reply.

Social Media in Business and Society

Social Media in Business and Society Most organizations tend to look upon social media as a threat, where some even opt to ban the usage from the workplace altogether. The idea behind it being that employees would be given the opportunity to waste time online, chat, and possibly pose as a security threat to the organization. (Turban, 2011) (Smith, 2010) outlines risk of employees social media use at work, these can be both intentional or not and they could lead to legal and reputational risks for organisations. These have been categorised as three main problems: Use of social media cannot be fully regulated, monitored or controlled thus organisations are giving up control. Social media is a worldwide means of communication, once a negative post is online its only a matter of time till it goes viral thus reaching competitors, regulators and customers. Social media is emotional and employees can express their feelings of happiness and/or frustration. Furthermore, (Flynn, 2012) identifies the risks of having employees participating in social media by causing reputational damage, trigger lawsuits, cause humiliation, crush credibility, destroy careers, create electronic business records, and lead to productivity losses. (Dreher, 2014) argues that social media is not to be feared, but rather embraced and seen as an opportunity where employees can act as corporate advocates and brand ambassadors. If anything, it helps employees keep up to date with latest news related to the industry together with continuous knowledge development. Nonetheless, even though there are many studies that point out the benefits of social media, there is still no clear-cut decision whether it can influence work performance or whether it can fuel the social capital of the employees and help in knowledge transfer (Zhang, 2016). However, it cannot be denied that every organisation allowing social media at work will always have its fair deal of challenges to overcome. (Eliane Bucher, 2013) speaks about the health issues that can be encountered. Starting off with stating that there is so much information available on social media that professionals may face information overload. Not to mention the mix of work life with private life overlapping with social media. New technologies should improve workers efficiency and reduce stress levels however often the opposite occurs (Eliane Bucher, 2013). Technostress as referred to by (Brod, 1984). To be successful in the social media environment one needs to overcome the below 3 points otherwise technostress is formed: Techno-overload Increase in workload which could be actual or perceived. Techno-invasion Social media enables people to be constantly connected from almost every device. This can lead to the feeling of the need to be connected or online causing reduction in family time allowing work issues to invade the private life (Eliane Bucher, 2013). Techno-uncertainty Social media is constantly changing and therefore brings with it uncertainty as regards to what technologies and skills are needed to perform the job and what will they be in the future. Social media comes with many legal issues tied to it. These range from pre-employment to post employment. Wrong usage of social media will for sure lead to waste of time, inefficiency, reputation issues and negative image for the organisation. Some of the laws are outlined below by (Lieber, 2011): Employment Laws by tagging co-workers in certain provocative photos or videos, Defamation and Libel Laws by stating certain comments on co-workers or employers thus effecting their reputation., As stated in (Trott, 2009) a Microsoft Survey found that 41% of employers based their decision of not hiring an applicant based on what they found online in relation to their reputation. This is also known as Netrep. This constitutes a legal risk of discrimination in itself if the recruiter is basing decision on the netrep. Fair Credit Reporting Act by having interviewers friending an applicant on Facebook to acquire more information than is required for the job applied. Health Insurance Portability and Accountability Act by having a medical professional LinkIn with a patient. Uniform Trade Secrets Act by having employees discussing or commenting on social media about company internal only discussions or non-public projects. Employers can monitor the use of social media at work if the employees are informed in advance. Disciplinary actions can be taken once any abuse is being noticed. Policies should include what is allowed and what is considered as abuse (Trott, 2009). If the employees post on their personal accounts outside of office hours and such posts are in relation to work having a negative impact in some way to the employer or the organisation then there is still grounds for disciplinary action even though employees try to advocate for respect for private and family life, home and correspondence (article 8) or freedom of expression (article 10) from the Human Rights Act 1998. As discussed above, social media has its advantages and disadvantages and seeing that social media is here to stay organisations have little choices but to accept the new reality, address it and learn how to make good use of it. (Lieber, 2011), among others, identifies the following criteria that any organisation willing to harness social media must address: The creation and enforcement of solid social media policies within the organisations personnel addressing fair use, access during work time and general behaviour on social media (even during personal time). Directly using social media for the benefit of the organisation such as for recruitment, marketing and investigating competing organizations. Monitoring of key social networks to data mine information regarding your organisation (and potentially others as well), possibly using automated algorithms and software for maximum efficiency and accuracy. From the above-mentioned criteria, the first two deal with human resource aspect of social media where organizations lay out guidelines to their employees on how to use them, and they as the organizations can use social media directly for recruitment, marketing etc. However, as the third criteria suggests, to make most use of social networks organizations must make sure that any information/data being released on such platforms, is gathered and used effectively. It is important that an organization is always aware of what the average user is saying about their brand, effectively getting the general feel or mood while analysing the trends across time. The same principle could be applied to monitor competitors; possibly for example identifying any weak products which the competitors have and having your own similar product take advantage of the situation. Effective monitoring comes from generating good data. Data mining involves the following steps to make data meaningful for monitoring: (Raghav Bali, 2016) Removing unwanted data and noise Transformation of the raw data into data that can be used for further processing Study the data and come up with patterns that can give further insight to our data Represent the data in a way that is useful to companies or to who the data intended for. There are different data mining techniques which can be used to monitor social media use. Social media is a form of real time communication therefore an effective monitoring tool needs to monitor and provide alerts as things happen. Most text mining tools make use of search engines to go through social media sites and collect information related to the keywords or interests. (Mark My Words article) Text Analytics (Text/Data Mining)   Ã‚   Text analytics involves a complex and elaborate number of steps to strip down conversations into separate words and analyse the way these words are being used, positive or negative and even derive patterns from collected data. When we search for a movie and receive some other movie recommendations that technique is using text mining. Text Mining is made up of Data Mining (Information retrieval, Natural Language Processing Machine learning) + Text Data (Emails, Tweets, News Articles, Websites, Blogs etc.) Figure 1: Text Mining (Charu C. Aggarwal, 2012) As indicated in Figure 1, Stop Word Removal and Stemming eliminate the generic and less meaningful words form a phrase, this helps categorizing different words with same meaning as see, seen and being seen. Bag of Words (BOW) is having words separated from the sentence and each word having a numerical value which represents its importance. Limitations (Charu C. Aggarwal, 2012) outlines several limitations that can be observed and future in-depth research is required: The real-time posts on social media are a very important resource as mining data in real time as it is being posted can yield many advantages. This however remains a challenge for when these posts are not conducted from work computers or from outside work. Social media is very unstructured and some applications like twitter even limit the amount of characters per post. This brings about problems of text recognition when short length words are used like gnite gr8 etc. Social media allows different ways to express opinions or emotions these could be through images, videos and tags making the text analytics much more complex and difficult in its pre-processing stage. Method 1: Keyword Search (Rappaport, 2010) Organisations can decide which keywords they want to monitor, these may be chosen based on what is important for that company, it could be their products or emotional states. Social media is a very unstructured place containing noise and unwanted data for our data mining process. This form of search is good to capture keywords and try and form a meaning of these words and the frequency used however its very hard to come up with what is the users intent. For that reason, we then consider a more complex search method called Sentiment Analysis. Method 2: Sentiment Analysis and Emotion Analysis Sentiment Analysis is the process of identifying sentiment in text and analyse it. There are three types of sentiment analysis (Walaa Medhat, 2014): Document Level Analyse the entire document as one topic and form an opinion or sentiment on the entire document Sentence Level Analyse sentiment in each sentence Aspect Level Analyse sentiment in respect to entities as you can have more than one aspect in a sentence for the same entity. For this study, we are focusing our research on Sentence Level analysis using Semantic search. Semantic Search: Semantic search goes beyond the traditional keyword search by providing a meaning to a phrase and makes use of a wide range of resources to interpret the phrase and thus providing a more accurate result. Some examples of semantic search in our daily lives: Conversational searches:   Figure 2: Conversational Search (Google, 2017) Auto Correct spelling mistakes: Figure 3: Auto Correct (Google, 2017) Display information in graphics format: Figure 4: Information in graphics format (Google, 2017) (Charu C. Aggarwal, 2012) outlines some challenges that are encountered when going through mining. These are the difficulty in recognising opinions, subjective phrases and emotions. Opinion mining challenges. When using semantic search method on a post one needs to understand that the post can contain all the following: Positive opinions I like the computer I bought, it has a very clear screen Negative opinions however my wife thinks its too expensive Different targets The targets in the positive opinions relate to the computer and the screen whereas the targets in the negative opinions are the price Different opinion holders The positive opinions are mine however the negative opinions are of my wife Subjectivity mining challenges Posts are also made up of objective and subjective comments. Subjective expressions like opinions, desire, assumptions amongst others may not contain opinions or may not express any positive or negative comments. Emotions mining challenges Emotions (love, joy, anger, fear, sadness, happiness and more) fall under a form of subjective expression. Sometimes emotions give no opinions in a phrase. To observe the usefulness and ideal approach towards the analysis of social media related posts and messaging, a software algorithm was designed and partially developed to illustrate this scenario. The idea behind this software is to have the user write inside a textbox, mimicking an actual employee typing using a company machine, while the system monitors such text and acts per what it registers. Therefore, this tool will be presented as a standalone software/algorithm concept, emulating an actual activity of a possible employee, and as such must be adapted accordingly to make use of it in a real-life situation. The basic principle of the solution proposed is made up of three modules: The key logger that monitors the users input at runtime and effects certain rules The keyword and semantic analysis on the data gathered The storage of produced analysis and log The following flowchart outlines the lifecycle of said solution, followed by a detailed analysis of each component mentioned above, as well as possible ways on how it can be further enhanced to produce even more accurate results. The flow of the proposed solution. Created using draw.io (https://www.draw.io/) Collecting and Processing Data In this solution, key logging is used to monitor the data inputted by the user, which is a constant monitoring of the keystrokes registered by ones activity, and registered as a stream of text ready to be dissected and analysed as required. The main advantage of using such a strategy is that data is collected and used in real-time, making it ideal for scenarios where an alarm (for example a negative post related to work) needs to be raised as quickly as possible to the relevant personnel, providing a detailed log of what the employee has typed (through the key logger) eliminating the need to monitor and access the relevant social media to check what has been posted. Note: there are other strategies one can pursuit to monitor the users activity, such as firewall policies or general network surveillance, however in real-life situations such solutions can prove rather difficult to setup due to the expertise required; while web encryption and proxy services makes it even harder to effectively monitor the traffic generated by the users. A key logger, even if effective, generates a lot of unneeded garbage beyond the scope of social media. For example, an employee working on his station would be constantly registering keystrokes which the logger is then adding them up to its own text stream. This could prove to be very problematic for three main reasons: The logger would begin to amass a significant amount of storage space, unless the key logger is given a limit of how much information it can hold and removing old data to make up space for the new data, but than some information can get permanently lost. The analysis of the text stream generated can be quite intensive, which can significantly affect the performance of the machine doing the analysis, especially when considering that the analysis is assumed to be processed on the users machine which most probably isnt very well suited for such intensive work. Furthermore, following the previous point, the garbage log is being analysed too needlessly. The chances are that an employee would spend very little time on social media, thus logging and analysing the work-related activity is quite pointless for such a scope. To overcome the above-mentioned issues, the proposed solution makes use of predefined social media trigger keywords i.e. a list of social media websites such as Facebook, Twitter, LinkedIn etc., where depending on such triggers being hit or not, the key logger will have two states, passive monitoring and active monitoring. When the tool is running normally, the key logger is in a passive state keeping only the last 30 characters in its memory, without processing the stream. The only thing it does however, is to constantly check the stream read from the textbox in the tool against the trigger keywords, and if any of the keywords is found to have been registered then the key logger would go into active state. While in this state the key logger would increase its maximum capacity, and begin to log every keystroke while constantly analysing the feed. The key logger will go back to passive state when the predefined character limit is reached or enough time has passed. Following this logic, only a set of keystrokes would be registered, reducing the chance of collecting and processing unneeded information while maintaining the workload and storage use of the machine to a minimum. Note: in this approach once the key logger goes into active state, it is monitoring and analysing the feed at runtime locally, and this could prove to be quite intensive depending on the parameters set and the overall performance of the users machines. Organizations implementing this solution can opt to have the log analysed after the key loggers goes back into passive state and therefore analysing the data only once. Better yet, since the solution assumes that the key logger is analysing the data locally, instead the logs can be sent to a common server and be analysed as a scheduled task. Once this data is captured through the key logger the feed can be processed by means of the methods discussed earlier (Method 1 and 2). Based on the outcome we store the data in our information system and align the data based on the organisations social policy. Approaching data analysis using keyword and semantic methods The designed software makes use of two different types of analysis algorithms, keyword based and semantic based, and are used together to try and cancel each others limitations and thus providing much more accurate results. Keyword based analysis The more traditional keyword analysis algorithm consists of having a list of keywords i.e. a predefined set of texts, and hit the data to be analysed against that list to determine whether any keywords have been hit and at what frequency. For example, having a text (representing the data) analysed against a list of negative texts (the keywords) would provide a set of statistical information which could be used to evaluate how negative the text is, which is conceptually what a social media monitoring tool should be trying to achieve. However, the major flaw of this analysis algorithm within the context of social media monitoring, is that keyword based analysis is far too broad and prone to false alarms if not controlled. Having the data gathered from the key logger (therefore filtered to social media activity) analysed against a set of negative texts, the statistical information produced may not be relevant to the organizations interest. An employee could simply be posting a feed about how bad the weather is and how much s/he hates it, which the keyword analysis algorithm would recognize as negative and report accordingly. In the proposed solution, the keyword based algorithm uses two different sets of keywords against the gathered data, with the aim to filter the batches of logged texts by relevance. The first set consists of a list of works related text, such as work, job, company, [company name] etc. i.e. every keyword that could somehow link the user to the organization implementing the solution. In the second set, a list of keywords/texts associated with negativity are stored, such as bored, unhappy, hate, dull, sick and tired etc. When the data passed along through the key logger reaches the keyword analysis module, it would first check the log against the first set and therefore determine whether the data fed is of any relevance to work, and if not simply do nothing. On the other hand, if any of the keywords from the first set is hit, it means that the data inputted is relevant and therefore must be analysed further. In this case, the tool would analyse the entire log within the key logger (which is currently in an active state as described in the previous section) and extract the statistical information with regards to the second set. The flow of the full keyword based algorithm adapted in the tool Created using draw.io (https://www.draw.io/) Examples Keywords to assume: First Set (work): WORK, JOB Second Set (negative): BORED, UNHAPPY, SAD, HATE, DULL, TIRED, SICK AND TIRED, ANNOYED, FED UP Example 1: Input Hate this weather, its severely effecting my mood. Constantly feeling tired and sad. Output None Example 2: Input At work and bored. Wish I could find a better job, this one is just so annoying. Output BORED x 1 [full log] Example 3: Input Never a dull moment at work. At the end of the day, the management brought in pizzas, fresh doughnuts and beer. In a couple of hours, the food was gone leaving everyone too tired to move. Got to love this company, always making sure their employees are never bored and unhappy. Output DULL x 1 TIRED x 1 BORED x 1 UNHAPPY x 1 [full log] From the examples above one can note a few limitations concerning the keyword based analysis algorithm. In example 2 the logged text is alarming, which most probably would require the full attention of the responsible personnel, but due to the limited keywords, only a single piece of text was hit which would make the output seem not so alarming. Furthermore, the logged text had the word annoying which in the negative keyword set is listed as annoyed, but still this was not captured. Therefore, this means that this algorithm is highly dependent on the keywords lists and possible deviations of each text. In example 3 the output looks very alarming since the negative keywords list was hit 4 times, but the input is very positive. The algorithm was unable to take into consideration the context of how the negative words were used and simply counted the number of times they were encountered within the log, hence raising a false alarm. To overcome such limitations, other algorithms must be used in conjunction with the keyword based, where in this solution the semantic based approach is used to compliment the algorithm and try to provide more accurate results. Semantic based analysis As explained in previous sections, semantic analysis introduces a certain degree of understanding when analysing a given text, and this is achieved by giving meaning to what it is fed. In this proposed software algorithm, this type of analysis is used to evaluate the sentiment and emotion behind the fed input, and therefore can determine whether the users work related activity on social media is negative or positive, which by extension may be able to overcome the limitations of keyword based approach. Basic forms of semantic based algorithms used to analyse text in relation to sentiment and emotion, often providing a single value output denoted by a percentage, where 0% means that the text is absolutely negative and a 100% would indicate that without a doubt it is positive. However, semantic analysis is capable to go beyond a simple value, where some of which can produce a fully detailed report indicating the level of emotions for multiple types, such as anger, fearfulness and joy. The following is an example of such a report produced by the tool Tone Analyser offered by (Cloud, 2017). Example report of a semantic based algorithm offered by IBM Watson Developer Cloud Applying such an algorithm which produces a very detailed report, may be well beyond the scope of monitoring work related activity on social media. In the end, what the proposed solution is trying to achieve is to detect negative activity which would harm said organizations, that when detected, the log of that activity is passed along to the corresponding personnel with perhaps a brief report of the analysis. Another drawback to be considered in this scenario, is that light weight semantic algorithms are much less intensive than algorithms which consider different types of emotions when analysing a text, and given that in the solution such an analysis will be triggered almost constantly, having a heavy algorithm being triggered would result in a very negative experience to said users. This is why in the proposed solution a lighter semantic analysis is considered, that is the API provided by (ParallelDots, 2017). Note: one could argue that using a semantic analysis algorithm which produces a detailed report, could replace the entire algorithm which is using both the keyword based analysis and the light weight semantic based analysis. However, performance wise the latter would operate much smoother, and from a technical point of view considerably easier to setup. Note: in the proposed solution, the semantic analysis will be conditional to whether the keyword based algorithm is triggered or not, and therefore subject to the filter which is detecting whether the activity on social media is related to work or not. Examples using the sentiment analysis demo provided by (ParallelDots, 2017), which outputs single value percentages 0% being negative, while 100% being positive. Example 1: Input Hate this weather, its severely effecting my mood. Constantly feeling tired and sad. Output 0% Example 2: Input At work and bored. Wish I could find a better job, this one is just so annoying. Output 6% Example 3: Input Never a dull moment at work. At the end of the day, the management brought in pizzas, fresh doughnuts and beer. In a couple of hours, the food was gone leaving everyone too tired to move. Got to love this company, always making sure their employees are never bored and unhappy. Output 79% Classifying severity based on score and frequency of words Thus far, the algorithm detected negative activity on social media relating to work, using both keywords and semantic analysis. However, the term negative can be rather broad and it may be the case that the organization would not want to be alerted for every minor negative activity, since that will become counterproductive. As such the proposed algorithm has a threshold mechanism which determines whether to send in alerts or not. The threshold settings are two. The minimum number of negative words the activity must contain, and the minimum percentage of negativity to be considered. Right after the key logger is finished monitoring the social media activity, if work related activity is logged, the system evaluates the log based on the threshold set by the administrators of the system, and proceed accordingly. Using same parameters of previous example for keyword and semantic based approaches. The thresholds are set as follows: Minimum Keywords 1, Minimum Semantic Percentage 30%. Example 1: Input Hate this weather, its severely effecting my mood. Constantly feeling tired and sad. Output None (not work related) Alert No Example 2: Input At work and bored. Wish I could find a better job, this one is just so annoying. Output Keywords hit: 1 Semantic: 6% Alert Yes Example 3: Input Never a dull moment at work. At the end of the day, the management brought in pizzas, fresh doughnuts and beer. In a couple of hours, the food was gone leaving everyone too tired to move. Got to love this comp

History of the Conflict In Sudan and the Role of the United Nations Ess

History of the Conflict In Sudan and the Role of the United Nations Introduction Sudan is Africa’s largest state and has been involved in conflict of various origins for varying periods of time. The paper will trace the origin and evolution of Sudan’s two most significant wars: the north-south civil war and the current conflict in the Darfur region that is now gaining international notoriety. Additionally, the UN System that is in place in Sudan will be analyzed anatomically. Ultimately the paper seeks to unearth ideas on what needs to happen going forward in order to improve the Darfur situation, as well as identify key inefficiencies in the UN’s approach to delivering aid. History of the Crises In Sudan Sudan is divided between an Arabic, Muslim north and an African south which is largely Christian or animist. Tension between these two realities has caused Sudan to know only 11 years of peace since gaining independence from 1956. The instability brought on by Sudan’s independence began to take shape in the months leading up to victory over colonization. Southern troops became fearful of domination by the north and began to mutiny. The southern mutinies were put down but following independence strife in the south continued as a rebel group known as the Anya-Nya fiercely sought either autonomy or outright succession. Efforts of the Anya-Nya continued until 1972 when President Numeiry of Sudan signed the Addis Ababa accord with the rebels resulting in three provinces within Southern Sudan that were given a significant degree of autonomy. Following this breakthrough negotiation, peace fell over Sudan up to 1983 when President Numeiry changed his stance wherein he not only instituted Islamic law in the country... ...://www.unsudanig.org/system/index.jsp. â€Å"United Nations System in Sudan: Information Pack.† http://www.unsudanig.org/system/index.jsp?agency=FAO http://www.unsudanig.org/system/index.jsp?agency=OCHA http://news.amnesty.org/index/engafr540042003. â€Å"Sudan: Urgent call for Commission of Inquiry in Darfur as situation deteriorates.† http://www.unsudanig.org/system/index.jsp?agency=OHCHR http://www.unsudanig.org/system/index.jsp?agency=UNHCR http://www.unsudanig.org/system/index.jsp?agency=UNDP http://www.unsudanig.org/system/index.jsp?agency=UNFPA http://www.unsudanig.org/system/index.jsp?agency=UNICEF http://www.unsudanig.org/system/index.jsp?agency=UNIDO http://www.unsudanig.org/system/index.jsp?agency=UNMAS http://www.unsudanig.org/system/index.jsp?agency=WHO http://news.amnesty.org/pages/sudan â€Å"Civilians Under Threat In Darfur.†

The Beneficiality of Computer :: Essays Papers

The Beneficiality of Computer The Computer The Most Beneficial Invention Over the Last 200 Years From the beginning of our country over 200 years ago until the present time I feel that the most beneficial invention to mankind has been the computer. The computer is beneficial in many different aspects of life such as: education, business, health, and communications. Computers are very beneficial to education in our world today. Computer classes are taught in every school in the United States. They help children get ready for the fast paced world of technology. If you don’t know how to use a computer these days there is a good chance that you will not be able to find a job. The Internet is a great way to access information for research or for general enlightenment. There are also programs such as cd-rom encyclopedias, dictionaries, and novels. There are also programs to help students with math, English, science, or any other school subject you can think of. These days you can even get a master’s degree from an accredited university online. Those are some ways computers are beneficial to education. In this day in age computers are very beneficial in the business world. Without computers many businesses would not be able to function. Businesses rely on computers to keep records, store data, make complex mathematical calculations, and run sophisticated machinery. Computers also provide new business and employment possibilities. They are good for the economy and create many jobs. Through the Internet computers allow companies to do business overseas without having to go by ship or airplane. Those are just some of the many ways computers are beneficial to the business world. In our modern world computers are also very useful to the healthcare industry. Computers help in the research, and manufacture of new drugs and treatments. They run the machines that analyze chemical compounds used in the development of new medicines. Computers are also used in healthcare in hands on applications. They run machines that keep people alive such as heart monitors, respirators, dialysis machines, and prenatal care units. Without computers in the healthcare industry a lot less people would survive their illnesses or accidents. Communication is also an area in which computers have made a profound influence. Computers, with the use of the Internet, can reach people all over the globe free of cost in just a matter of seconds with the use of e-mail.

Poliomyelitis Essay -- Communicable Diseases, Nursing

Brief summary of poliomyelitis The purpose of this paper is identifying poliomyelitis which is a fecal-oral group communicable disease worldwide and discussing health interventions to control and eliminate outbreaks and considering ethical dilemmas. The pathogen of poliomyelitis is poliovirus, an enterovirous that is transmitted by fecal-oral route through feces. Respiratory inhalation occurs and the virus initially replicates in the oro-pharynx and then invades the gastrointestinal tract. It can be transmitted via fecal-oral, airborne, water-borne processes, and asymptomatic carrier. (WHO, 2009) Clinical manifestations range from asymptomatic self-limited disease and mild symptoms of combined fever, malaise, fatigue, nausea, headache, flu-like symptoms, stiff neck and back, and pain to severe fetal paralytic disease which may cause death from respiratory failure. Children under five years of age are most at risk. (WHO, 2010) Paralytic poliomyelitis produces muscles pain and affects the lower part of body like the legs. Poliovirus incubates for five to thirty days and becomes communicable two days after disclosure and can remain communicable up to six weeks. Poliomyelitis can be diagnosis by clinical evaluation of viral cultures like spinal fluids, stool samples, throat swabs, and serum antibody levels. (Webber, R., 2010). Public health interventions In Unites States, poliomyelitis is not endemic therefore even one case can become an epidemic. Geographically more than 125 countries remained polio-endemic in 1988. Overall global incidents have decreased by 99% since 1988. Between 2009 and 2010 twenty three poliomyelitis free countries were re-infected due to imported virus. The countries of Afghanistan, India, Nigeria and Paki... ...rol: A global perspective (3rded) Cambridge, MA: CABI publishing World Health Organization - Case definition for the four diseases requiring notification in all circumstances under the International Health Regulation (2005). Retrieved from http://www.who.int/ihr/Case_Definitions.pdf POLIOMYELITIS Report Immediately Retrieved from health.utah.gov/epi/diseases/polio/plan/PolioPlan061510.pdf The Centers for Disease Control and Prevention (CDC) studied the illness and death rates before and after widespread implementation of national vaccine recommendations (in place before 2005) for 13 vaccine-preventable diseases; diphtheria, pertussis, tetanus, poliomyelitis, measles, mumps, rubella (including congenital rubella syndrome), invasive Haemophilus influenzae type b (Hib), acute hepatitis B, hepatitis A, varicella (chickenpox), Streptococcus pneumoniae and smallpox.

Concept Map Tuberculosis

Schiffman, George. (07, 2011). Tuberculosis. Retrieved from http://www. medicinenet. com/tuberculosis/page4. htm Tuberculosis. (01, 2013). Retrieved from http://www. mayoclinic. com/health/tuberculosis/DS00372/DSECTION=treatments-and-drugs Vyas, Jatin M. (11, 2012). Pulmonary Tuberculosis. Retrieved from http://www. ncbi. nlm. nih. gov/pubmedhealth/PMH0001141/ Schiffman, George. (07, 2011).Tuberculosis. Retrieved from http://www. medicinenet. com/tuberculosis/page4. htm Tuberculosis. (01, 2013). Retrieved from http://www. mayoclinic. com/health/tuberculosis/DS00372/DSECTION=treatments-and-drugs Vyas, Jatin M. (11, 2012). Pulmonary Tuberculosis. Retrieved from http://www. ncbi. nlm. nih. gov/pubmedhealth/PMH0001141/ IMPLEMENTATION -Assess respiratory rate every 10-15 minutes Continuously note chest movement and use of accessory muscles during respiration -Auscultate breath sounds and note any areas with adventitious sounds, especially wet crackles -Document any respiratory secretions such as sputum: amount, character, and consistency -Keep patient in high Fowler’s position to allow optimum breathing -Check for obstructions or accumulation of sputum -Ask patient level of discomfort/pain on a scale of 1-10 -Record medication administrations and if therapeutic effects are occurring -Describe procedures and treatment expectations Encourage patient to follow drug regimens IMPLEMENTATION -Assess respiratory rate every 10-15 minutes -Continuously note chest movement and use of accessory muscles during respiration -Auscultate breath sounds and note any areas with adventitious sounds, especially wet crackles -Document any respiratory secretions such as sputum: amount, character, and consistency -Keep patient in high Fowler’s position to allow optimum breathing -Check for obstructions or accumulation of sputum -Ask patient level of discomfort/pain on a scale of 1-10 Record medication administrations and if therapeutic effects are occurring -Describe procedur es and treatment expectations -Encourage patient to follow drug regimens PLANNING -Goals include treating any abnormal results such as dyspnea, abnormal breath sounds, irritability, and reducing or eliminating sputum levels -Give patient therapeutic effects regarding abnormalities found with little or no side effects -Help patient in making lifestyle changes that include making a safer work and home environment and getting the people who have the most contact with the patient treatment PLANNING Goals include treating any abnormal results such as dyspnea, abnormal breath sounds, irritability, and reducing or eliminating sputum levels -Give patient therapeutic effects regarding abnormalities found with little or no side effects -Help patient in making lifestyle changes that include making a safer work and home environment and getting the people who have the most contact with the patient treatment TUBERCULOSIS TUBERCULOSIS DIAGNOSIS Ineffective airway clearance related to poor cough ef fort as evidenced by abnormal breath sounds and dyspnea -Risk for infection related to settled secretions as evidenced by wet adventitious lung sounds such as crackles, and excessive sputum -Deficient knowledge related to condition, treatment plan, self-care and discharge needs as evidenced by questions/requests for information, statements about the problem, and the development of preventable complications DIAGNOSIS -Ineffective airway clearance related to poor cough effort as evidenced by abnormal breath sounds and dyspnea -Risk for infection related to settled ecretions as evidenced by wet adventitious lung sounds such as crackles, and excessive sputum -Deficient knowledge related to condition, treatment plan, self-care and discharge needs as evidenced by questions/requests for information, statements about the problem, and the development of preventable complications ASSESSMENT -Check for vitals; check for abnormal breath sounds, especially for wet crackles on inspiration -Assess for dyspnea, if using accessory muscles for respirations, or if the pt has elevated shoulders -Assess level, color, and consistency of any sputum Check for restlessness, irritability, or anxiousness -Report history of the patient, any existing illnesses such as pneumonia, cancer, family hx, workplace, home life, and lifestyle ASSESSMENT -Check for vitals; check for abnormal breath sounds, especially for wet crackles on inspiration -Assess for dyspnea, if using accessory muscles for respirations, or if the pt has elevated shoulders -Assess level, color, and consistency of any sputum -Check for restlessness, irritability, or anxiousness Report history of the patient, any existing illnesses such as pneumonia, cancer, family hx, workplace, home life, and lifestyle NURSING PROCESS NURSING PROCESS EVALUATION -Assess if medication and procedures are performing therapeutic effects -Check for levels of discomfort/pain on a scale of 1-10, make sure vitals and lab results are within normal ra nges -Check if patient’s secretion amount diminished or stopped -Assess if patient’s restlessness and irritability was alleviated -Check if patient is continuously taking prescribed medications to prevent spread of disease EVALUATION Assess if medication and procedures are performing therapeutic effects -Check for levels of discomfort/pain on a scale of 1-10, make sure vitals and lab results are within normal ranges -Check if patient’s secretion amount diminished or stopped -Assess if patient’s restlessness and irritability was alleviated -Check if patient is continuously taking prescribed medications to prevent spread of disease ETIOLOGY -Caused by the bacteria Mycobacterium tuberculosis (M. uberculosis) by breathing in air droplets from a cough or sneeze of an infected person, resulting in primary TB -Risk factors include those who life with others who have active TB, poor or homeless people, elderly, infants, nursing home residents, prison inmates, alc oholics, IV drug users, those with malnutrition, working in health care, workers in refugee camps -Factors that elevate chances include diabetes, kidney disease, cancer, chemotherapy, and certain types of drugs ETIOLOGY Caused by the bacteria Mycobacterium tuberculosis (M. tuberculosis) by breathing in air droplets from a cough or sneeze of an infected person, resulting in primary TB -Risk factors include those who life with others who have active TB, poor or homeless people, elderly, infants, nursing home residents, prison inmates, alcoholics, IV drug users, those with malnutrition, working in health care, workers in refugee camps -Factors that elevate chances include diabetes, kidney disease, cancer, chemotherapy, and certain types of drugsPATHOGENESIS -Droplets of fluid containing tubercle bacilli are released into the air and are taken into the nasal passages and lungs of a susceptible person nearby -Once inhaled, tubercle bacilli reach alveoli where macrophages take them up; ba cilli then multiply and spread through lymph vessels into the lymph nodes and finally to distant organs; can remain ‘alive’ or become ‘inactive’ -Immune system responds which causes damage to the tissues; cells attack the bacilli, thus killing the infectionPATHOGENESIS -Droplets of fluid containing tubercle bacilli are released into the air and are taken into the nasal passages and lungs of a susceptible person nearby -Once inhaled, tubercle bacilli reach alveoli where macrophages take them up; bacilli then multiply and spread through lymph vessels into the lymph nodes and finally to distant organs; can remain ‘alive’ or become ‘inactive’ -Immune system responds which causes damage to the tissues; cells attack the bacilli, thus killing the infectionSIGNS/SYMPTOMS -Common symptoms include unintentional weight loss, fatigue, fever, night sweats, chills, loss of appetite -Cough persisting three weeks or more, coughing up blood or sput um, or chest pain when breathing or coughing -If spread, TB of the spine leads to back pain and TB of the kidneys cause blood in the urine SIGNS/SYMPTOMS Common symptoms include unintentional weight loss, fatigue, fever, night sweats, chills, loss of appetite -Cough persisting three weeks or more, coughing up blood or sputum, or chest pain when breathing or coughing -If spread, TB of the spine leads to back pain and TB of the kidneys cause blood in the urine COMPLICATIONS -Medicines for TB can cause side effects such as liver problems, changes in vision, orange/brown colored tears or urine, rash -TB of the bones: joint destruction -TB of the brain: meningitis; swelling TB of liver or kidneys: impaired filtering of waste -TB of the heart: inflammation; fluid collections; impaired pumping abilities; cardiac tamponade COMPLICATIONS -Medicines for TB can cause side effects such as liver problems, changes in vision, orange/brown colored tears or urine, rash -TB of the bones: joint destru ction -TB of the brain: meningitis; swelling -TB of liver or kidneys: impaired filtering of waste -TB of the heart: inflammation; fluid collections; impaired pumping abilities; cardiac tamponade TREATMENT/MANAGEMENT Patient recommended to stay in isolation and on bed rest until no longer contagious -Inactive TB: antibiotic called isoniazid (INH) is prescribed for six to twelve months; not prescribed to pregnant women; can cause liver damage and peripheral neuropathy -Active TB: INH is also prescribed along with rifampin, ethambutol, pyrazinamide; may also receive streptomycin; may be taken from months to years -Drug resistant TB: everything with active TB with several other drugs; longer treatment; may require surgery to remove damaged lung tissue TREATMENT/MANAGEMENT Patient recommended to stay in isolation and on bed rest until no longer contagious -Inactive TB: antibiotic called isoniazid (INH) is prescribed for six to twelve months; not prescribed to pregnant women; can cause li ver damage and peripheral neuropathy -Active TB: INH is also prescribed along with rifampin, ethambutol, pyrazinamide; may also receive streptomycin; may be taken from months to years -Drug resistant TB: everything with active TB with several other drugs; longer treatment; may require surgery to remove damaged lung tissue

Operating System (Assignment)

1. In a multiprogramming and time sharing environment, several users share the system simultaneously. This situation can results in various security problems. a. What are the two such problems? Ans: The two problems in Multiprogramming and time sharing environment are Stealing or copying a user's files; Writing over another program's (belonging to another user or to the OS) area in memory; Using system resources (CPU, disk space) without proper accounting; Causing the printer to mix output by sending data while some other user's file is printing. ttp://wiki. answers. com/Q/What_are_the_main_two_problems_in_multiprogramming_environment_when_processes_are_run_concurrently_and_share_the_resources b. Can we ensure the same degree of security in a time shared machine as in a dedicated machine? Explain. Ans: No, because time-shared machines are far less secure, and are very easy to overload the buffers. Also they are much slower to catch a virus. http://wiki. answers. com/Q/Can_we_ensure_t he_same_security_in_a_time-shared_machine_as_in_a_dedicated_machine . The issue of resource utilization shows up in differenct forms in different types of operating systems. List what resources must be manged carefully in the following settings: a. Mainframe or Minicomputer systems Ans: Memory, CPU, Storage b. Workstations connected to servers Ans: Storage, Network Bandwidth c. Handheld computers Ans: Memory, CPU, Storage, Power 3. Describe the difference symmetric and asymmetric multiprocessing. What are three advantages and one disadvantages of multiprocessor system? Ans:The difference between symmetric and asymmetric multiprocessing is that in Symmetric processing treats all processors as equals; I/O can be processed on any of them, while Asymmetric processing designates one CPU as the master, which is the only one capable of performing I/O; the master distributes computational work among the other CPUs. Advantagesmultiprocessor system: ?Can save money, by sharing power supplies, housings, and peripherals ? Can execute programs more quickly ?Can have increased reliability Disadvantagesmultiprocessor system: More complex in both hardware and software. Additional CPU cycles are required to manage the cooperation, so per-CPU efficiency goes down. http://www. studymode. com/essays/Os-Assignment-419243. html 4. Distinguish between the client server and peer to peer models of distributed systems. Ans: A client-server model can be defined as a centralized environment, where all users, objects, resources, and so on are administered in a centralized location and can, if configured, use any network resources on any workstation on the domain. while a Peer-to-peer model can be defined as a decentralized environment, where the user must be assigned permissions on each workstation in order to access any available resources. 5. What is the purpose of interrupts? What are the difference between a trap and an interrupt? Can traps be generated intentionally by a user program ? If so, for what purpose? Ans: The difference between Interrupt and Trap is that Interrupt is a hardware-generated signal that changes the flow within the system. While a trap is a software-generated interrupt. 6.Define the essential properties of the following types of operating systems. a. Batch: Jobs with similar needs are batched together and run through the computer as a group, by an operator or automatic job sequencer. Performance is increased by attempting to keep CPU and I/O devices busy at all times through buffering, off-line operation, spooling, and multiprogramming. b. Interactive: Composed of many short transactions with input and output read/written on the screen; the results and timing of the next transaction may be unpredictable. Note that a urely interactive system (no time-sharing) only has one user; e. g. , a PC). c. Time-sharing: Uses CPU scheduling and multiprogramming to provide economical interactive use of a system. The CPU switches rapidly from one user to another. d. Real-time: The system must respond to inputs/commands within a fixed amount of time to ensure correct performance. Input is typically read from sensors. e. Network:Consists of two or more computers that are linked in order to share resources (such as printers and CDs), exchange files, or allow electronic communications.The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams. f. Parallel:More than one event happening at a time. It is usually contrasted with serial, meaning only one event happening at a time. g. Distributed: Divides computation up among several computers. The computers do not share memory or a clock; they communicate with each other over communication lines (e. g. , high-speed bus, telephone line). h. Clustered: i. Handheld:A handheld computer is a computer that can conveniently be stored in a pocket (of sufficient size) and used while you're holding it.

Mcdonalds Coffee Case

The McDonald’s Coffee Case Back in 1992 when Stella Liebeck spilled McDonald’s coffee on herself, she never intended to sue. She simply asked for money to cover her medical charges and for the time her daughter was out of work caring for her. When she received an inadequate response from McDonald’s, that’s when she sought an attorney. This case has turned out to be one of the most misunderstood cases of our times. In Stella Liebeck’s defense, it can be said that McDonald’s should not have been serving coffee so hot.As mentioned in the article â€Å"McDonald’s policy at the time was to serve its coffee at 180 to 190 degrees Fahrenheit. † After hearing a statistic like that, it’s hard to believe that anyone would enjoy drinking something that hot. â€Å"180 degrees Fahrenheit is hot enough to cause severe third degree burns in less than a second. † That is exactly what the coffee ended up doing to Stella Liebeck. She ended up with burns all over her buttocks and thigh. In McDonald’s defense, they can use the principle of Caveat Emptor or Buyer Beware. McDonald’s can say that once they hand out their coffee they have no control over what happens to it.McDonald’s was not the one to actually spill the coffee on Stella Liebeck, she did it to herself. She knew that it was very hot, and she should have used more caution when opening up her coffee. Using the â€Å"Reasonable Person† principle, people are expecting the coffee that they buy to be very hot. A person would not deliberately pour hot coffee on themselves because that will hurt badly. In this case the â€Å"Reasonable Person† theory does not apply as much because she did not spill coffee on herself on purpose. The â€Å"Industry Standard† principle seems to have the greatest range of a course of action.Depending on the size of the corporation will dictate their course of action. For example, a global company like McDonald’s would be more able to pay money to a burn victim rather than an owner of a deli. To determine the results for this case, two precedents were used. Buyer beware prevailed in one case, and in the second case the court ruled that a warning should have been given to the victim. It is safe to say that in both of those cases and the McDonald’s case, if a warning had been issued then the result would have probably never happened.

Physics Notes

Gravitation Gravitational field strength at a point is defined as the gravitational force per unit mass at that point. Newton's law of gravitation: The (mutual) gravitational force F between two point masses M and m separated by a distance r is given by F =| GMm| (where G: Universal gravitational constant)| | r2| | or, the gravitational force of between two point masses is proportional to the product of their masses ; inversely proportional to the square of their separation. Gravitational field strength at a point is the gravitational force per unit mass at that point. It is a vector and its S. I. unit is N kg-1.By definition, g = F / m By Newton Law of Gravitation, F = GMm / r2 Combining, magnitude of g = GM / r2 Therefore g = GM / r2, M = Mass of object â€Å"creating† the field Example 1: Assuming that the Earth is a uniform sphere of radius 6. 4 x 106 m and mass 6. 0 x 1024 kg, find the gravitational field strength g at a point: (a) on the surface, g = GM / r2 = (6. 67 ? 1 0-11)(6. 0 x 1024) / (6. 4 x 106)2 = 9. 77ms-2 (b) at height 0. 50 times the radius of above the Earth's surface. g = GM / r2 = (6. 67 ? 10-11)(6. 0 x 1024) / ( (1. 5 ? 6. 4 x 106)2 = 4. 34ms-2 Example 2: The acceleration due to gravity at the Earth's surface is 9. 0ms-2. Calculate the acceleration due to gravity on a planet which has the same density but twice the radius of Earth. g = GM / r2 gP / gE = MPrE2 / MErP2 = (4/3) ? rP3rE2? P / (4/3) ? rE3rP2? E = rP / rE = 2 Hence gP = 2 x 9. 81 = 19. 6ms-2 Assuming that Earth is a uniform sphere of mass M. The magnitude of the gravitational force from Earth on a particle of mass m, located outside Earth a distance r from the centre of the Earth is F = GMm / r2. When a particle is released, it will fall towards the centre of the Earth, as a result of the gravitational force with an acceleration ag. FG = mag ag = GM / r2Hence ag = g Thus gravitational field strength g is also numerically equal to the acceleration of free fall. Example 1: A ship is at rest on the Earth's equator. Assuming the earth to be a perfect sphere of radius R and the acceleration due to gravity at the poles is go, express its apparent weight, N, of a body of mass m in terms of m, go, R and T (the period of the earth's rotation about its axis, which is one day). At the North Pole, the gravitational attraction is F = GMEm / R2 = mgo At the equator, Normal Reaction Force on ship by Earth = Gravitational attraction – centripetal force N = mgo – mR? = mgo – mR (2? / T)2 Gravitational potential at a point is defined as the work done (by an external agent) in bringing a unit mass from infinity to that point (without changing its kinetic energy). ? = W / m = -GM / r Why gravitational potential values are always negative? As the gravitational force on the mass is attractive, the work done by an ext agent in bringing unit mass from infinity to any point in the field will be negative work {as the force exerted by the ext agent is opp osite in direction to the displacement to ensure that ? KE = 0} Hence by the definition of negative work, all values of ? re negative. g = -| d? | = – gradient of ? -r graph {Analogy: E = -dV/dx}| | dr| | Gravitational potential energy U of a mass m at a point in the gravitational field of another mass M, is the work done in bringing that mass m {NOT: unit mass, or a mass} from infinity to that point. ; U = m ? = -GMm / r Change in GPE, ? U = mgh only if g is constant over the distance h; {; h;; radius of planet} otherwise, must use: ? U = m? f-m? i | Aspects| Electric Field| Gravitational Field| 1. | Quantity interacting with or producing the field| Charge Q| Mass M| 2. Definition of Field Strength| Force per unit positive charge E = F / q| Force per unit mass g = F / M| 3. | Force between two Point Charges or Masses| Coulomb's Law: Fe = Q1Q2 / 4 or2| Newton's Law of Gravitation: Fg = G (GMm / r2)| 4. | Field Strength of isolated Point Charge or Mass| E = Q / 4 or2| g = G (G M / r2)| 5. | Definition of Potential| Work done in bringing a unit positive charge from infinity to the point; V = W /Q| Work done in bringing a unit mass from infinity to the point; ? = W / M| 6. | Potential of isolated Point Charge or Mass| V = Q / 4 or| ? -G (M / r)| 7. | Change in Potential Energy| ? U = q ? V| ? U = m | Total Energy of a Satellite = GPE + KE = (-GMm / r) + ? (GMm / r) Escape Speed of a Satellite By Conservation of Energy, Initial KE| +| Initial GPE| =| Final KE| +| Final GPE| (? mvE2)| +| (-GMm / r)| =| (0)| +| (0)| Thus escape speed, vE = v(2GM / R) Note : Escape speed of an object is independent of its mass For a satellite in circular orbit, â€Å"the centripetal force is provided by the gravitational force† {Must always state what force is providing the centripetal force before following eqn is used! Hence GMm / r2 = mv2 / r = mr? 2 = mr (2? / T)2 A satellite does not move in the direction of the gravitational force {ie it stays in its circular orbi t} because: the gravitational force exerted by the Earth on the satellite is just sufficient to cause the centripetal acceleration but not enough to also pull it down towards the Earth. {This explains also why the Moon does not fall towards the Earth} Geostationary satellite is one which is always above a certain point on the Earth (as the Earth rotates about its axis. For a geostationary orbit: T = 24 hrs, orbital radius (; height) are fixed values from the centre of the Earth, ang velocity w is also a fixed value; rotates fr west to east. However, the mass of the satellite is NOT a particular value ; hence the ke, gpe, ; the centripetal force are also not fixed values {ie their values depend on the mass of the geostationary satellite. } A geostationary orbit must lie in the equatorial plane of the earth because it must accelerate in a plane where the centre of Earth lies since the net orce exerted on the satellite is the Earth's gravitational force, which is directed towards the c entre of Earth. {Alternatively, may explain by showing why it's impossible for a satellite in a non-equatorial plane to be geostationary. } Thermal Physics Internal Energy: is the sum of the kinetic energy of the molecules due to its random motion ; the potential energy of the molecules due to the intermolecular forces. Internal energy is determined by the values of the current state and is independent of how the state is arrived at. You can read also Thin Film Solar CellThus if a system undergoes a series of changes from one state A to another state B, its change in internal energy is the same, regardless of which path {the changes in the p ; V} it has taken to get from A to B. Since Kinetic Energy proportional to temp, and internal energy of the system = sum of its Kinetic Energy and Potential Energy, a rise in temperature will cause a rise in Kinetic Energy and thus an increase in internal energy. If two bodies are in thermal equilibrium, there is no net flow of heat energy between them and they have the same temperature. NB: this does not imply they must have the same internal energy as internal energy depends also on the number of molecules in the 2 bodies, which is unknown here} Thermodynamic (Kelvin) scale of temperature: theoretical scale that is independent of the properties of any particular substance. An absolute scale of temp is a temp scale which does not depend on the property of any particular subs tance (ie the thermodynamic scale) Absolute zero: Temperature at which all substances have a minimum internal energy {NOT: zero internal energy. } T/K = T/ °C + 273. 15, by definition of the Celsius scale.Specific heat capacity is defined as the amount of heat energy needed to produce unit temperature change {NOT: by 1 K} for unit mass {NOT: 1 kg} of a substance, without causing a change in state. c = Q / m? T Specific latent heat of vaporisation is defined as the amount of heat energy needed to change unit mass of a substance from liquid phase to gaseous phase without a change of temperature. Specific latent heat of fusion is defined as the amount of heat energy needed to change unit mass of a substance from solid phase to liquid phase without a change of temperature L = Q / m {for both cases of vaporisation ; melting}The specific latent heat of vaporisation is greater than the specific latent heat of fusion for a given substance because * During vaporisation, there is a greater increase in volume than in fusion, * Thus more work is done against atmospheric pressure during vaporisation, * The increase in vol also means the INCREASE IN THE (MOLECULAR) POTENTIAL ENERGY, ; hence, internal energy, during vaporisation more than that during melting, * Hence by 1st Law of Thermodynamics, heat supplied during vaporisation more than that during melting; hence lv ; lf {since Q = ml = ?U – W}. Note: 1. the use of comparative terms: greater, more, and; 2. the increase in internal energy is due to an increase in the PE, NOT KE of molecules 3. the system here is NOT to be considered as an ideal gas system Similarly, you need to explain why, when a liq is boiling, thermal energy is being supplied, and yet, the temp of the liq does not change. | Melting| Boiling| Evaporation| Occurrence| Throughout the substance, at fixed temperature and pressure| On the surface, at all temperatures|Spacing(vol) ; PE of molecules| Increase slightly| Increase significantly| | Tempera ture ; hence KE of molecules| Remains constant during process| Decrease for remaining liquid| First Law of Thermodynamics: The increase in internal energy of a system is equal to the sum of the heat supplied to the system and the work done on the system. ?U = W + Q| ? U: Increase in internal energy of the system Q: Heat supplied to the system W: work done on the system| {Need to recall the sign convention for all 3 terms} Work is done by a gas when it expands; work is done on a gas when it is ompressed. W = area under pressure – volume graph. For constant pressure {isobaric process}, Work done = pressure x ? Volume Isothermal process: a process where T = const {? U = 0 for ideal gas} ? U for a cycle = 0 {since U ? T, ; ? T = 0 for a cycle } Equation of state for an ideal gas: p V = n R T, where T is in Kelvin {NOT:  °C}, n: no. of moles. p V = N k T, where N: no. of molecules, k:Boltzmann const Ideal Gas: a gas which obeys the ideal gas equation pV = nRT FOR ALL VALUES OF P , V ; T Avogadro constant: defined as the number of atoms in 12g of carbon-12.It is thus the number of particles (atoms or molecules) in one mole of substance. For an ideal gas, internal energy U = Sum of the KE of the molecules only {since PE = 0 for ideal gas} U = N x? m ;c2; = N x (3/2)kT {for monatomic gas} * U depends on T and number of molecules N * U ? T for a given number of molecules Ave KE of a molecule, ? m ;c2; ? T {T in K: not  °C} Dynamics Newton's laws of motion: Newton's First Law Every body continues in a state of rest or uniform motion in a straight line unless a net (external) force acts on it. Newton's Second LawThe rate of change of momentum of a body is directly proportional to the net force acting on the body, and the momentum change takes place in the direction of the net force. Newton's Third Law When object X exerts a force on object Y, object Y exerts a force of the same type that is equal in magnitude and opposite in direction on object X. The two force s ALWAYS act on different objects and they form an action-reaction pair. Linear momentum and its conservation: Mass: is a measure of the amount of matter in a body, ; is the property of a body which resists change in motion.Weight: is the force of gravitational attraction (exerted by the Earth) on a body. Linear momentum: of a body is defined as the product of its mass and velocity ie p = m v Impulse of a force (I): is defined as the product of the force and the time ? t during which it acts ie I = F x ? t {for force which is const over the duration ? t} For a variable force, the impulse I = Area under the F-t graph { ? Fdt; may need to â€Å"count squares†} Impulse is equal in magnitude to the change in momentum of the body acted on by the force.Hence the change in momentum of the body is equal in mag to the area under a (net) force-time graph. {Incorrect to define impulse as change in momentum} Force: is defined as the rate of change of momentum, ie F = [ m (v – u) ] / t = ma or F = v dm / dt The {one} Newton: is defined as the force needed to accelerate a mass of 1 kg by 1 m s-2. Principle of Conservation of Linear Momentum: When objects of a system interact, their total momentum before and after interaction are equal if no net (external) force acts on the system. * The total momentum of an isolated system is constant m1 u1 + m2 u2 = m1 v1 + m2 v2 if net F = 0 {for all collisions } NB: Total momentum DURING the interaction/collision is also conserved. (Perfectly) elastic collision: Both momentum ; kinetic energy of the system are conserved. Inelastic collision: Only momentum is conserved, total kinetic energy is not conserved. Perfectly inelastic collision: Only momentum is conserved, and the particles stick together after collision. (i. e. move with the same velocity. ) For all elastic collisions, u1 – u2 = v2 – v1 ie. relative speed of approach = relative speed of separation or, ? m1u12 + ? m2u22 = ? m1v12 + ? 2v22 In inelastic collisions, total energy is conserved but Kinetic Energy may be converted into other forms of energy such as sound and heat energy. Current of Electricity Electric current is the rate of flow of charge. {NOT: charged particles} Electric charge Q passing a point is defined as the product of the (steady) current at that point and the time for which the current flows, Q = I t One coulomb is defined as the charge flowing per second pass a point at which the current is one ampere. Example 1: An ion beam of singly-charged Na+ and K+ ions is passing through vacuum. If the beam current is 20 ?A, calculate the total number of ions passing any fixed point in the beam per second. (The charge on each ion is 1. 6 x 10-19 C. ) Current, I = Q / t = Ne / t where N is the no. of ions and e is the charge on one ion. No. of ions per second = N / t = I / e = (20 x 10-6) / (1. 6 x 10-19) = 1. 25 x 10-14 Potential difference is defined as the energy transferred from electrical energy to other forms of e nergy when unit charge passes through an electrical device, V = W / Q P. D. = Energy Transferred / Charge = Power / Current or, is the ratio of the power supplied to the device to the current flowing, V = P / IThe volt: is defined as the potential difference between 2 pts in a circuit in which one joule of energy is converted from electrical to non-electrical energy when one coulomb passes from 1 pt to the other, ie 1 volt = One joule per coulomb Difference between Potential and Potential Difference (PD): The potential at a point of the circuit is due to the amount of charge present along with the energy of the charges. Thus, the potential along circuit drops from the positive terminal to negative terminal, and potential differs from points to points. Potential Difference refers to the difference in potential between any given two points.For example, if the potential of point A is 1 V and the potential at point B is 5 V, the PD across AB, or VAB , is 4 V. In addition, when there is no energy loss between two points of the circuit, the potential of these points is same and thus the PD across is 0 V. Example 2: A current of 5 mA passes through a bulb for 1 minute. The potential difference across the bulb is 4 V. Calculate: (a) The amount of charge passing through the bulb in 1 minute. Charge Q = I t = 5 x 10-3 x 60 = 0. 3 C (b) The work done to operate the bulb for 1 minute. Potential difference across the bulb = W / Q 4 = W / 0. Work done to operate the bulb for 1 minute = 0. 3 x 4 = 1. 2 J Electrical Power, P = V I = I2 / R = V2 / R {Brightness of a lamp is determined by the power dissipated, NOT: by V, or I or R alone} Example 3: A high-voltage transmission line with a resistance of 0. 4 ? km-1 carries a current of 500 A. The line is at a potential of 1200 kV at the power station and carries the current to a city located 160 km from the power station. Calculate (a) the power loss in the line. The power loss in the line P = I2 R = 5002 x 0. 4 x 160 = 16 MW (b) the fraction of the transmitted power that is lost.The total power transmitted = I V = 500 x 1200 x 103 = 600 MW The fraction of power loss = 16 / 600 = 0. 267 Resistance is defined as the ratio of the potential difference across a component to the current flowing through it , R = VI {It is NOT defined as the gradient of a V-I graph; however for an ohmic conductor, its resistance equals the gradient of its V-I graph as this graph is a straight line which passes through the origin} The Ohm: is the resistance of a resistor if there is a current of 1 A flowing through it when the pd across it is 1 V, ie, 1 ? = One volt per ampere Example 4:In the circuit below, the voltmeter reading is 8. 00 V and the ammeter reading is 2. 00 A. Calculate the resistance of R. Resistance of R = V / I = 8 / 2 = 4. 0 ? | | Temperature characteristics of thermistors: The resistance (i. e. the ratio V / I) is constant because metallic conductors at constant temperature obey Ohm's Law. | As V increases, the temperature increases, resulting in an increase in the amplitude of vibration of ions and the collision frequency of electrons with the lattice ions. Hence the resistance of the filament increases with V. | A thermistor is made from semi-conductors.As V increases, temperature increases. This releases more charge carriers (electrons and holes) from the lattice, thus reducing the resistance of the thermistor. Hence, resistance decreases as temperature increases. | In forward bias, a diode has low resistance. In reverse bias, the diode has high resistance until the breakdown voltage is reached. | Ohm's law: The current in a component is proportional to the potential difference across it provided physical conditions (eg temp) stay constant. R = ? L / A {for a conductor of length l, uniform x-sect area A and resistivity ? Resistivity is defined as the resistance of a material of unit cross-sectional area and unit length. {From R = ? l / A , ? = RA / L} Example 5: Calculate the resistanc e of a nichrome wire of length 500 mm and diameter 1. 0 mm, given that the resistivity of nichrome is 1. 1 x 10-6 ? m. Resistance, R = ? l / A = [(1. 1 x 10-6)(500 x 10-3)] / ? (1 x 10-3 / 2)2 = 0. 70 ? Electromotive force (Emf) is defined as the energy transferred / converted from non-electrical forms of energy into electrical energy when unit charge is moved round a complete circuit. ie EMF = Energy Transferred per unit charge E = WQEMF refers to the electrical energy generated from non-electrical energy forms, whereas PD refers to electrical energy being changed into non-electrical energy. For example, EMF Sources| Energy Change| PD across| Energy Change| Chemical Cell| Chem ; Elec| Bulb| Elec ; Light| Generator| Mech ; Elec| Fan| Elec ; Mech| Thermocouple| Thermal ; Elec| Door Bell| Elec ; Sound| Solar Cell| Solar ; Elec| Heating element| Elec ; Thermal| Effects of the internal resistance of a source of EMF: Internal resistance is the resistance to current flow within the power source.It reduces the potential difference (not EMF) across the terminal of the power supply when it is delivering a current. Consider the circuit below: The voltage across the resistor, V = IR, The voltage lost to internal resistance = Ir Thus, the EMF of the cell, E = IR + Ir = V + Ir Therefore If I = 0A or if r = 0? , V = E Motion in a Circle Kinematics of uniform circular motion Radian (rad) is the S. I. unit for angle, ? and it can be related to degrees in the following way. In one complete revolution, an object rotates through 360 ° , or 2? rad. As the object moves through an angle ? , with respect to the centre of rotation, this angle ? s known as the angular displacement. Angular velocity (? ) of the object is the rate of change of angular displacement with respect to time. ? = ? / t = 2? / T (for one complete revolution) Linear velocity, v, of an object is its instantaneous velocity at any point in its circular path. v = arc length / time taken = r? / t = r? * The directi on of the linear velocity is at a tangent to the circle described at that point. Hence it is sometimes referred to as the tangential velocity * ? is the same for every point in the rotating object, but the linear velocity v is greater for points further from the axis.A body moving in a circle at a constant speed changes velocity {since its direction changes}. Thus, it always experiences an acceleration, a force and a change in momentum. Centripetal acceleration a = r? 2 = v2 / r {in magnitude} Centripetal force Centripetal force is the resultant of all the forces that act on a system in circular motion. {It is not a particular force; â€Å"centripetal† means â€Å"centre-seeking†. Also, when asked to draw a diagram showing all the forces that act on a system in circular motion, it is wrong to include a force that is labelled as â€Å"centripetal force†. } Centripetal force, F = m r ? 2 = mv2 / r {in magnitude}A person in a satellite orbiting the Earth experience s â€Å"weightlessness† although the gravi field strength at that height is not zero because the person and the satellite would both have the same acceleration; hence the contact force between man ; satellite / normal reaction on the person is zero {Not because the field strength is negligible}. D. C. Circuits Circuit Symbols: Open Switch| Closed Switch| Lamp| Cell| Battery| Voltmeter| Resistor| Fuse| Ammeter| Variable resistor| Thermistor| Light dependent resistor (LDR)| Resistors in Series: R = R1 + R2 + †¦ Resistors in Parallel: 1/R = 1/R1 + 1/R2 + †¦ Example 1:Three resistors of resistance 2 ? , 3 ? and 4 ? respectively are used to make the combinations X, Y and Z shown in the diagrams. List the combinations in order of increasing resistance. Resistance for X = [1/2 + 1/(4+3)]-1 = 1. 56 ? Resistance for Y = 2 + (1/4 + 1/3)-1 = 3. 71 ? Resistance for Z = (1/3 + 1/2 + 1/4)-1 = 0. 923 ? Therefore, the combination of resistors in order of increasing resistance is Z X Y. Example: Referring to the circuit drawn, determine the value of I1, I and R, the combined resistance in the circuit. E = I1 (160) = I2 (4000) = I3 (32000) I1 = 2 / 160 = 0. 0125 A I2 = 2 / 4000 = 5 x 10-4 AI3 = 2 / 32000 = 6. 25 x 10-5 ASince I = I1 + I2 + I3, I = 13. 1 mAApplying Ohm’s Law, R = 213. 1 x 10-3 = 153 ? | | Example: A battery with an EMF of 20 V and an internal resistance of 2. 0 ? is connected to resistors R1 and R2 as shown in the diagram. A total current of 4. 0 A is supplied by the battery and R2 has a resistance of 12 ?. Calculate the resistance of R1 and the power supplied to each circuit component. E – I r = I2 R2 20 – 4 (2) = I2 (12) I2 = 1A Therefore, I1 = 4 – 1 = 3 AE – I r = I1 R1 12 = 3 R1 Therefore, R1 = 4Power supplied to R1 = (I1)2 R1 = 36 W Power supplied to R2 = (I2)2 R2 = 12 W| |For potential divider with 2 resistors in series, Potential drop across R1, V1 = R1 / (R1 + R2) x PD across R1 ; R2 Potential drop acro ss R2, V1 = R2 / (R1 + R2) x PD across R1 ; R2 Example: Two resistors, of resistance 300 k? and 500 k? respectively, form a potential divider with outer junctions maintained at potentials of +3 V and -15 V. Determine the potential at the junction X between the resistors. The potential difference across the 300 k? resistor = 300 / (300 + 500) [3 – (-15)] = 6. 75 V The potential at X = 3 – 6. 75 = -3. 75 V A thermistor is a resistor whose resistance varies greatly with temperature.Its resistance decreases with increasing temperature. It can be used in potential divider circuits to monitor and control temperatures. Example: In the figure on the right, the thermistor has a resistance of 800 ? when hot, and a resistance of 5000 ? when cold. Determine the potential at W when the temperature is hot. When thermistor is hot, potential difference across it = [800 / (800 + 1700)] x (7 – 2) = 1. 6 VThe potential at W = 2 + 1. 6 V = 3. 6 V| | A Light dependent resistor (LDR) is a resistor whose resistance varies with the intensity of light falling on it. Its resistance decreases with increasing light intensity.It can be used in a potential divider circuit to monitor light intensity. Example: In the figure below, the resistance of the LDR is 6. 0 M in the dark but then drops to 2. 0 k in the light Determine the potential at point P when the LDR is in the light. In the light the potential difference across the LDR= [2k / (3k + 2k)] x (18 – 3) = 6 VThe potential at P = 18 – 6= 12 V| | The potential difference along the wire is proportional to the length of the wire. The sliding contact will move along wire AB until it finds a point along the wire such that the galvanometer shows a zero reading.When the galvanometer shows a zero reading, the current through the galvanometer (and the device that is being tested) is zero and the potentiometer is said to be â€Å"balanced†. If the cell has negligible internal resistance, and if the potent iometer is balanced, EMF / PD of the unknown source, V = [L1 / (L1 + L2)] x E Example: In the circuit shown, the potentiometer wire has a resistance of 60 ?. Determine the EMF of the unknown cell if the balanced point is at B. Resistance of wire AB= [0. 65 / (0. 65 + 0. 35)] x 60 = 39 ? EMF of the test cell= [39 / (60 + 20)] x 12| Work, Energy and PowerWork Done by a force is defined as the product of the force and displacement (of its point of application) in the direction of the force W = F s cos ? Negative work is said to be done by F if x or its compo. is anti-parallel to F If a variable force F produces a displacement in the direction of F, the work done is determined from the area under F-x graph. {May need to find area by â€Å"counting the squares†. } By Principle of Conservation of Energy, Work Done on a system = KE gain + GPE gain + Work done against friction} Consider a rigid object of mass m that is initially at rest.To accelerate it uniformly to a speed v, a cons tant net force F is exerted on it, parallel to its motion over a displacement s. Since F is constant, acceleration is constant, Therefore, using the equation: v2 = u2 +2as, as = 12 (v2 – u2) Since kinetic energy is equal to the work done on the mass to bring it from rest to a speed v, The kinetic energy, EK| = Work done by the force F = Fs = mas = ? m (v2 – u2)| Gravitational potential energy: this arises in a system of masses where there are attractive gravitational forces between them.The gravitational potential energy of an object is the energy it possesses by virtue of its position in a gravitational field. Elastic potential energy: this arises in a system of atoms where there are either attractive or repulsive short-range inter-atomic forces between them. Electric potential energy: this arises in a system of charges where there are either attractive or repulsive electric forces between them. The potential energy, U, of a body in a force field {whether gravitationa l or electric field} is related to the force F it experiences by: F = – dU / dx.Consider an object of mass m being lifted vertically by a force F, without acceleration, from a certain height h1 to a height h2. Since the object moves up at a constant speed, F is equal to mg. The change in potential energy of the mass| = Work done by the force F = F s = F h = m g h| Efficiency: The ratio of (useful) output energy of a machine to the input energy. ie =| Useful Output Energy| x100% =| Useful Output Power| x100%| | Input Energy| | Input Power| | Power {instantaneous} is defined as the work done per unit time. P =| Total Work Done| =| W| | Total Time| | t|Since work done W = F x s, P =| F x s| =| Fv| | t| | | * for object moving at const speed: F = Total resistive force {equilibrium condition} * for object beginning to accelerate: F = Total resistive force + ma Forces Hooke's Law: Within the limit of proportionality, the extension produced in a material is directly proportional to the force/load applied F = kx Force constant k = force per unit extension (F/x) Elastic potential energy/strain energy = Area under the F-x graph {May need to â€Å"count the squares†} For a material that obeys Hooke? s law, Elastic Potential Energy, E = ? F x = ? x2 Forces on Masses in Gravitational Fields: A region of space in which a mass experiences an (attractive) force due to the presence of another mass. Forces on Charge in Electric Fields: A region of space where a charge experiences an (attractive or repulsive) force due to the presence of another charge. Hydrostatic Pressure p = ? gh {or, pressure difference between 2 points separated by a vertical distance of h } Upthrust: An upward force exerted by a fluid on a submerged or floating object; arises because of the difference in pressure between the upper and lower surfaces of the object.Archimedes' Principle: Upthrust = weight of the fluid displaced by submerged object. ie Upthrust = Volsubmerged x ? fluid x g Frict ional Forces: * The contact force between two surfaces = (friction2 + normal reaction2)? * The component along the surface of the contact force is called friction * Friction between 2 surfaces always opposes relative motion {or attempted motion}, and * Its value varies up to a maximum value {called the static friction} Viscous Forces: * A force that opposes the motion of an object in a fluid * Only exists when there is (relative) motion Magnitude of viscous force increases with the speed of the object Centre of Gravity of an object is defined as that pt through which the entire weight of the object may be considered to act. A couple is a pair of forces which tends to produce rotation only. Moment of a Force: The product of the force and the perpendicular distance of its line of action to the pivot Torque of a Couple: The produce of one of the forces of the couple and the perpendicular distance between the lines of action of the forces. (WARNING: NOT an action-reaction pair as they a ct on the same body. ) Conditions for Equilibrium (of an extended object): 1.The resultant force acting on it in any direction equals zero 2. The resultant moment about any point is zero If a mass is acted upon by 3 forces only and remains in equilibrium, then 1. The lines of action of the 3 forces must pass through a common point 2. When a vector diagram of the three forces is drawn, the forces will form a closed triangle (vector triangle), with the 3 vectors pointing in the same orientation around the triangle. Principle of Moments: For a body to be in equilibrium, the sum of all the anticlockwise moments about any point must be equal to the sum of all the clockwise moments about that same point.Measurement Base quantities and their units; mass (kg), length (m), time (s), current (A), temperature (K), amount of substance (mol): Base Quantities| SI Units| | Name| Symbol| Length| metre| m| Mass| kilogram| kg| Time| second| s| Amount of substance| mole| mol| Temperature| Kelvin| K| C urrent| ampere| A| Luminous intensity| candela| cd| Derived units as products or quotients of the base units: Derived| Quantities Equation| Derived Units| Area (A)| A = L2| m2| Volume (V)| V = L3| m3| Density (? )| ? = m / V| kg m-3| Velocity (v)| v = L / t| ms-1| Acceleration (a)| a = ? v / t| ms-1 / s = ms-2|Momentum (p)| p = m x v| (kg)(ms-1) = kg m s-1| Derived Quantities| Equation| Derived Unit| Derived Units| | | Special Name| Symbol| | Force (F)| F = ? p / t| Newton| N| [(kg m s-1) / s = kg m s-2| Pressure (p)| p = F / A| Pascal| Pa| (kg m s-2) / m2 = kg m-1 s-2| Energy (E)| E = F x d| joule| J| (kg m s-2)(m) = kg m2 s-2| Power (P)| P = E / t| watt| W| (kg m2 s-2) / s = kg m2 s-3| Frequency (f)| f = 1 / t| hertz| Hz| 1 / s = s-1| Charge (Q)| Q = I x t| coulomb| C| A s| Potential Difference (V)| V = E / Q| volt| V| (kg m2 s-2) / A s = kg m2 s-3 A-1| Resistance (R)| R = V / I| ohm| ? (kg m2 s-3 A-1) / A = kg m2 s-3 A-2| Prefixes and their symbols to indicate decimal sub-multipl es or multiples of both base and derived units: Multiplying Factor| Prefix| Symbol| 10-12| pico| p| 10-9| nano| n| 10-6| micro| ? | 10-3| milli| m| 10-2| centi| c| 10-1| decid| d| 103| kilo| k| 106| mega| M| 109| giga| G| 1012| tera| T| Estimates of physical quantities: When making an estimate, it is only reasonable to give the figure to 1 or at most 2 significant figures since an estimate is not very precise. Physical Quantity| Reasonable Estimate| Mass of 3 cans (330 ml) of Coke| 1 kg|Mass of a medium-sized car| 1000 kg| Length of a football field| 100 m| Reaction time of a young man| 0. 2 s| * Occasionally, students are asked to estimate the area under a graph. The usual method of counting squares within the enclosed area is used. (eg. Topic 3 (Dynamics), N94P2Q1c) * Often, when making an estimate, a formula and a simple calculation may be involved. EXAMPLE 1: Estimate the average running speed of a typical 17-year-old? s 2. 4-km run. velocity = distance / time = 2400 / (12. 5 x 60) = 3. 2 ? 3 ms-1 EXAMPLE 2: Which estimate is realistic? | Option| Explanation|A| The kinetic energy of a bus travelling on an expressway is 30000J| A bus of mass m travelling on an expressway will travel between 50 to 80 kmh-1, which is 13. 8 to 22. 2 ms-1. Thus, its KE will be approximately ? m(182) = 162m. Thus, for its KE to be 30000J: 162m = 30000. Thus, m = 185kg, which is an absurd weight for a bus; ie. This is not a realistic estimate. | B| The power of a domestic light is 300W. | A single light bulb in the house usually runs at about 20W to 60W. Thus, a domestic light is unlikely to run at more than 200W; this estimate is rather high. | C| The temperature of a hot oven is 300 K. 300K = 27 0C. Not very hot. | D| The volume of air in a car tyre is 0. 03 m3. | | Estimating the width of a tyre, t, is 15 cm or 0. 15 m, and estimating R to be 40 cm and r to be 30 cm,volume of air in a car tyre is = ? (R2 – r2)t = ? (0. 42 – 0. 32)(0. 15) = 0. 033 m3 ? 0. 03 m3 (t o one sig. fig. )| Distinction between systematic errors (including zero errors) and random errors and between precision and accuracy: Random error: is the type of error which causes readings to scatter about the true value. Systematic error: is the type of error which causes readings to deviate in one direction from the true value.Precision: refers to the degree of agreement (scatter, spread) of repeated measurements of the same quantity. {NB: regardless of whether or not they are correct. } Accuracy: refers to the degree of agreement between the result of a measurement and the true value of the quantity. | ; ; R Error Higher ; ; ; ; ; ; Less Precise ; ; ;| v v vS Error HigherLess Accuratev v v| | | | | | Assess the uncertainty in a derived quantity by simple addition of actual, fractional or percentage uncertainties (a rigorous statistical treatment is not required). For a quantity x = (2. 0  ± 0. 1) mm,Actual/ Absolute uncertainty, ? x =  ± 0. 1 mm Fractional uncertainty, ? x x = 0. 05 Percentage uncertainty, ? xx 100% = 5 % If p = (2x + y) / 3 or p = (2x – y) / 3, ? p = (2? x + ? y) / 3 If r = 2xy3 or r = 2x / y3, ? r / r = ? x / x + 3? y / y Actual error must be recorded to only 1 significant figure, ; The number of decimal places a calculated quantity should have is determined by its actual error. For eg, suppose g has been initially calculated to be 9. 80645 ms-2 ; ? g has been initially calculated to be 0. 04848 ms-2. The final value of ? g must be recorded as 0. 5 ms-2 {1 sf }, and the appropriate recording of g is (9. 81  ± 0. 05) ms-2. Distinction between scalar and vector quantities: | Scalar| Vector| Definition| A scalar quantity has a magnitude only. It is completely described by a certain number and a unit. | A vector quantity has both magnitude and direction. It can be described by an arrow whose length represents the magnitude of the vector and the arrow-head represents the direction of the vector. | Examples| Distance, speed, mass , time, temperature, work done, kinetic energy, pressure, power, electric charge etc. Common Error:Students tend to associate kinetic energy and pressure with vectors because of the vector components involved. However, such considerations have no bearings on whether the quantity is a vector or scalar. | Displacement, velocity, moments (or torque), momentum, force, electric field etc. | Representation of vector as two perpendicular components: In the diagram below, XY represents a flat kite of weight 4. 0 N. At a certain instant, XY is inclined at 30 ° to the horizontal and the wind exerts a steady force of 6. 0 N at right angles to XY so that the kite flies freely.By accurate scale drawing| By calculations using sine and cosine rules, or Pythagoras? theorem| Draw a scale diagram to find the magnitude and direction of the resultant force acting on the kite. R = 3. 2 N (? 3. 2 cm) at ? = 112 ° to the 4 N vector. | Using cosine rule, a2 = b2 + c2 – 2bc cos A R2 = 42 + 62 -2( 4)(6)(cos 30 °) R = 3. 23 NUsing sine rule: a / sin A = b / sin B 6 / sin ? = 3. 23 / sin 30 ° ? = 68 ° or 112 ° = 112 ° to the 4 N vector| Summing Vector Components| | Fx = – 6 sin 30 ° = – 3 NFy = 6 cos 30 ° – 4 = 1. 2 NR = v(-32 + 1. 22) = 3. 23 Ntan ? = 1. 2 / 3 = 22 °R is at an angle 112 ° to the 4 N vector. (90 ° + 22 °)|Kinematics Displacement, speed, velocity and acceleration: Distance: Total length covered irrespective of the direction of motion. Displacement: Distance moved in a certain direction. Speed: Distance travelled per unit time. Velocity: is defined as the rate of change of displacement, or, displacement per unit time {NOT: displacement over time, nor, displacement per second, nor, rate of change of displacement per unit time} Acceleration: is defined as the rate of change of velocity. Using graphs to find displacement, velocity and acceleration: * The area under a velocity-time graph is the change in displacement. The gr adient of a displacement-time graph is the {instantaneous} velocity. * The gradient of a velocity-time graph is the acceleration. The ‘SUVAT' Equations of Motion The most important word for this chapter is SUVAT, which stands for: * S (displacement), * U (initial velocity), * V (final velocity), * A (acceleration) and * T (time) of a particle that is in motion. Below is a list of the equations you MUST memorise, even if they are in the formula book, memorise them anyway, to ensure you can implement them quickly. 1. v = u +at| derived from definition of acceleration: a = (v – u) / t| 2. | s = ? (u + v) t| derived from the area under the v-t graph| 3. | v2 = u2 + 2as| derived from equations (1) and (2)| 4. | s = ut + ? at2| derived from equations (1) and (2)| These equations apply only if the motion takes place along a straight line and the acceleration is constant; {hence, for eg. , air resistance must be negligible. } Motion of bodies falling in a uniform gravitational field with air resistance: Consider a body moving in a uniform gravitational field under 2 different conditions: Without Air Resistance:Assuming negligible air resistance, whether the body is moving up, or at the highest point or moving down, the weight of the body, W, is the only force acting on it, causing it to experience a constant acceleration. Thus, the gradient of the v-t graph is constant throughout its rise and fall. The body is said to undergo free fall. With Air Resistance: If air resistance is NOT negligible and if it is projected upwards with the same initial velocity, as the body moves upwards, both air resistance and weight act downwards. Thus its speed will decrease at a rate greater than . 81 ms-2 . This causes the time taken to reach its maximum height reached to be lower than in the case with no air resistance. The max height reached is also reduced. At the highest point, the body is momentarily at rest; air resistance becomes zero and hence the only force acting on it is the weight. The acceleration is thus 9. 81 ms-2 at this point. As a body falls, air resistance opposes its weight. The downward acceleration is thus less than 9. 81 ms-2. As air resistance increases with speed, it eventually equals its weight (but in opposite direction).From then there will be no resultant force acting on the body and it will fall with a constant speed, called the terminal velocity. Equations for the horizontal and vertical motion: | x direction (horizontal – axis)| y direction (vertical – axis)| s (displacement)| sx = ux t sx = ux t + ? ax t2| sy = uy t + ? ay t2 (Note: If projectile ends at same level as the start, then sy = 0)| u (initial velocity)| ux| uy| v (final velocity)| vx = ux + axt (Note: At max height, vx = 0)| vy = uy + at vy2 = uy2 + 2asy| a (acceleration)| ax (Note: Exists when a force in x direction present)| ay (Note: If object is falling, then ay = -g)| (time)| t| t| Parabolic Motion: tan ? = vy / vx ?: direction of tangenti al velocity {NOT: tan ? = sy / sx } Forces Hooke's Law: Within the limit of proportionality, the extension produced in a material is directly proportional to the force/load applied F = kx Force constant k = force per unit extension (F/x) Elastic potential energy/strain energy = Area under the F-x graph {May need to â€Å"count the squares†} For a material that obeys Hooke? s law, Elastic Potential Energy, E = ? F x = ? k x2 Forces on Masses in Gravitational Fields: A region of space in which a mass experiences an (attractive) force due to the presence of another mass.Forces on Charge in Electric Fields: A region of space where a charge experiences an (attractive or repulsive) force due to the presence of another charge. Hydrostatic Pressure p = ? gh {or, pressure difference between 2 points separated by a vertical distance of h } Upthrust: An upward force exerted by a fluid on a submerged or floating object; arises because of the difference in pressure between the upper and l ower surfaces of the object. Archimedes' Principle: Upthrust = weight of the fluid displaced by submerged object. ie Upthrust = Volsubmerged x ? fluid x g Frictional Forces: The contact force between two surfaces = (friction2 + normal reaction2)? * The component along the surface of the contact force is called friction * Friction between 2 surfaces always opposes relative motion {or attempted motion}, and * Its value varies up to a maximum value {called the static friction} Viscous Forces: * A force that opposes the motion of an object in a fluid * Only exists when there is (relative) motion * Magnitude of viscous force increases with the speed of the object Centre of Gravity of an object is defined as that pt through which the entire weight of the object may be considered to act.A couple is a pair of forces which tends to produce rotation only. Moment of a Force: The product of the force and the perpendicular distance of its line of action to the pivot Torque of a Couple: The produ ce of one of the forces of the couple and the perpendicular distance between the lines of action of the forces. (WARNING: NOT an action-reaction pair as they act on the same body. ) Conditions for Equilibrium (of an extended object): 1. The resultant force acting on it in any direction equals zero 2. The resultant moment about any point is zero If a mass is acted upon by 3 forces only and remains in equilibrium, then 1.The lines of action of the 3 forces must pass through a common point 2. When a vector diagram of the three forces is drawn, the forces will form a closed triangle (vector triangle), with the 3 vectors pointing in the same orientation around the triangle. Principle of Moments: For a body to be in equilibrium, the sum of all the anticlockwise moments about any point must be equal to the sum of all the clockwise moments about that same point. Work, Energy and Power Work Done by a force is defined as the product of the force and displacement (of its point of application) in the direction of the force W = F s cos ?Negative work is said to be done by F if x or its compo. is anti-parallel to F If a variable force F produces a displacement in the direction of F, the work done is determined from the area under F-x graph. {May need to find area by â€Å"counting the squares†. } By Principle of Conservation of Energy, Work Done on a system = KE gain + GPE gain + Work done against friction} Consider a rigid object of mass m that is initially at rest. To accelerate it uniformly to a speed v, a constant net force F is exerted on it, parallel to its motion over a displacement s. Since F is constant, acceleration is constant, Therefore, using the equation: 2 = u2 +2as, as = 12 (v2 – u2) Since kinetic energy is equal to the work done on the mass to bring it from rest to a speed v, The kinetic energy, EK| = Work done by the force F = Fs = mas = ? m (v2 – u2)| Gravitational potential energy: this arises in a system of masses where there are at tractive gravitational forces between them. The gravitational potential energy of an object is the energy it possesses by virtue of its position in a gravitational field. Elastic potential energy: this arises in a system of atoms where there are either attractive or repulsive short-range inter-atomic forces between them.Electric potential energy: this arises in a system of charges where there are either attractive or repulsive electric forces between them. The potential energy, U, of a body in a force field {whether gravitational or electric field} is related to the force F it experiences by: F = – dU / dx. Consider an object of mass m being lifted vertically by a force F, without acceleration, from a certain height h1 to a height h2. Since the object moves up at a constant speed, F is equal to mg. The change in potential energy of the mass| = Work done by the force F = F s = F h = m g h|Efficiency: The ratio of (useful) output energy of a machine to the input energy. ie =| U seful Output Energy| x100% =| Useful Output Power| x100%| | Input Energy| | Input Power| | Power {instantaneous} is defined as the work done per unit time. P =| Total Work Done| =| W| | Total Time| | t| Since work done W = F x s, P =| F x s| =| Fv| | t| | | * for object moving at const speed: F = Total resistive force {equilibrium condition} * for object beginning to accelerate: F = Total resistive force + ma Wave Motion Displacement (y): Position of an oscillating particle from its equilibrium position.Amplitude (y0 or A): The maximum magnitude of the displacement of an oscillating particle from its equilibrium position. Period (T): Time taken for a particle to undergo one complete cycle of oscillation. Frequency (f): Number of oscillations performed by a particle per unit time. Wavelength (? ): For a progressive wave, it is the distance between any two successive particles that are in phase, e. g. it is the distance between 2 consecutive crests or 2 troughs. Wave speed (v): The sp eed at which the waveform travels in the direction of the propagation of the wave.Wave front: A line or surface joining points which are at the same state of oscillation, i. e. in phase, e. g. a line joining crest to crest in a wave. Ray: The path taken by the wave. This is used to indicate the direction of wave propagation. Rays are always at right angles to the wave fronts (i. e. wave fronts are always perpendicular to the direction of propagation). From the definition of speed, Speed = Distance / Time A wave travels a distance of one wavelength, ? , in a time interval of one period, T. The frequency, f, of a wave is equal to 1 / T Therefore, speed, v = ? / T = (1 / T)? f? v = f? Example 1: A wave travelling in the positive x direction is showed in the figure. Find the amplitude, wavelength, period, and speed of the wave if it has a frequency of 8. 0 Hz. Amplitude (A) = 0. 15 mWavelength (? ) = 0. 40 mPeriod (T) = 1f = 18. 0 ? 0. 125 sSpeed (v) =f? = 8. 0 x 0. 40 = 3. 20 m s-1A wa ve which results in a net transfer of energy from one place to another is known as a progressive wave. | | Intensity {of a wave}: is defined as the rate of energy flow per unit time {power} per unit cross-sectional area perpendicular to the direction of wave propagation.Intensity = Power / Area = Energy / (Time x Area) For a point source (which would emit spherical wavefronts), Intensity = (? m? 2xo2) / (t x 4? r2) where x0: amplitude ; r: distance from the point source. Therefore, I ? xo2 / r2 (Pt Source) For all wave sources, I ? (Amplitude)2 Transverse wave: A wave in which the oscillations of the wave particles {NOT: movement} are perpendicular to the direction of the propagation of the wave. Longitudinal wave: A wave in which the oscillations of the wave particles are parallel to the direction of the propagation of the wave.Polarisation is said to occur when oscillations are in one direction in a plane, {NOT just â€Å"in one direction†} normal to the direction of propag ation. {Only transverse waves can be polarized; longitudinal waves can’t. }Example 2: The following stationary wave pattern is obtained using a C. R. O. whose screen is graduated in centimetre squares. Given that the time-base is adjusted such that 1 unit on the horizontal axis of the screen corresponds to a time of 1. 0 ms, find the period and frequency of the wave. Period, T = (4 units) x 1. 0 = 4. 0 ms = 4. 0 x 10-3 sf = 1 / T = 14 x 10-3 250 Hz| | Superposition Principle of Superposition: When two or more waves of the same type meet at a point, the resultant displacement of the waves is equal to the vector sum of their individual displacements at that point. Stretched String A horizontal rope with one end fixed and another attached to a vertical oscillator. Stationary waves will be produced by the direct and reflected waves in the string. Or we can have the string stopped at one end with a pulley as shown below. Microwaves A microwave emitter placed a distance away from a metal plate that reflects the emitted wave.By moving a detector along the path of the wave, the nodes and antinodes could be detected. Air column A tuning fork held at the mouth of a open tube projects a sound wave into the column of air in the tube. The length of the tube can be changed by varying the water level. At certain lengths of the tube, the air column resonates with the tuning fork. This is due to the formation of stationary waves by the incident and reflected sound waves at the water surface. Stationary (Standing) Wave) is one * whose waveform/wave profile does not advance {move}, where there is no net transport of energy, and * where the positions of antinodes and nodes do not change (with time). A stationary wave is formed when two progressive waves of the same frequency, amplitude and speed, travelling in opposite directions are superposed. {Assume boundary conditions are met} | Stationary waves| Stationary Waves Progressive Waves| Amplitude| Varies from maximum at th e anti-nodes to zero at the nodes. | Same for all particles in the wave (provided no energy is lost). | Wavelength| Twice the distance between a pair of adjacent nodes or anti-nodes. The distance between two consecutive points on a wave, that are in phase. | Phase| Particles in the same segment/ between 2 adjacent nodes, are in phase. Particles in adjacent segments are in anti-phase. | All particles within one wavelength have different phases. | Wave Profile| The wave profile does not advance. | The wave profile advances. | Energy| No energy is transported by the wave. | Energy is transported in the direction of the wave. | Node is a region of destructive superposition where the waves always meet out of phase by ? radians. Hence displacement here is permanently zero {or minimum}.Antinode is a region of constructive superposition where the waves always meet in phase. Hence a particle here vibrates with maximum amplitude {but it is NOT a pt with a permanent large displacement! } Dist between 2 successive nodes / antinodes = ? / 2 Max pressure change occurs at the nodes {NOT the antinodes} because every node changes fr being a pt of compression to become a pt of rarefaction {half a period later} Diffraction: refers to the spreading {or bending} of waves when they pass through an opening {gap}, or round an obstacle (into the â€Å"shadow† region). Illustrate with diag} For significant diffraction to occur, the size of the gap ? ? of the wave For a diffraction grating, d sin ? = n ? , d = dist between successive slits {grating spacing} = reciprocal of number of lines per metre When a â€Å"white light† passes through a diffraction grating, for each order of diffraction, a longer wavelength {red} diffracts more than a shorter wavelength {violet} {as sin ? ? ? }. Diffraction refers to the spreading of waves as they pass through a narrow slit or near an obstacle. For diffraction to occur, the size of the gap should approximately be equal to the wavelengt h of the wave.Coherent waves: Waves having a constant phase difference {not: zero phase difference / in phase} Interference may be described as the superposition of waves from 2 coherent sources. For an observable / well-defined interference pattern, the waves must be coherent, have about the same amplitude, be unpolarised or polarised in the same direction, ; be of the same type. Two-source interference using: 1. Water Waves Interference patterns could be observed when two dippers are attached to the vibrator of the ripple tank.The ripples produce constructive and destructive interference. The dippers are coherent sources because they are fixed to the same vibrator. 2. Microwaves Microwave emitted from a transmitter through 2 slits on a metal plate would also produce interference patterns. By moving a detector on the opposite side of the metal plate, a series of rise and fall in amplitude of the wave would be registered. 3. Light Waves (Young? s double slit experiment) Since light is emitted from a bulb randomly, the way to obtain two coherent light sources is by splitting light from a single slit.The 2 beams from the double slit would then interfere with each other, creating a pattern of alternate bright and dark fringes (or high and low intensities) at regular intervals, which is also known as our interference pattern. Condition for Constructive Interference at a pt P: Phase difference of the 2 waves at P = 0 {or 2? , 4? , etc} Thus, with 2 in-phase sources, * implies path difference = n? ; with 2 antiphase sources: path difference = (n + ? )? Condition for Destructive Interference at a pt P: Phase difference of the 2 waves at P = ? { or 3? , 5? , etc } With 2 in-phase sources, + implies path difference = (n+ ? ), with 2 antiphase sources: path difference = n ? Fringe separation x = ? D / a, if a;;D {applies only to Young's Double Slit interference of light, ie, NOT for microwaves, sound waves, water waves} Phase difference betw the 2 waves at any pt X {be tw the central & 1st maxima) is (approx) proportional to the dist of X from the central maxima. Using 2 sources of equal amplitude x0, the resultant amplitude of a bright fringe would be doubled {2Ãâ€"0}, & the resultant intensity increases by 4 times {not 2 times}. { IResultant ? (2 x0)2 } Electric FieldsElectric field strength / intensity at a point is defined as the force per unit positive charge acting at that point {a vector; Unit: N C-1 or V m-1} E = F / q > F = qE * The electric force on a positive charge in an electric field is in the direction of E, while * The electric force on a negative charge is opposite to the direction of E. * Hence a +ve charge placed in an electric field will accelerate in the direction of E and gain KE {& simultaneously lose EPE}, while a negative charge caused to move (projected) in the direction of E will decelerate, ie lose KE, { & gain EPE}. Representation of electric fields by field lines | | | | | Coulomb's law: The (mutual) electric force F acting between 2 point charges Q1 and Q2 separated by a distance r is given by: F = Q1Q2 / 4 or2 where ? 0: permittivity of free space or, the (mutual) electric force between two point charges is proportional to the product of their charges ; inversely proportional to the square of their separation. Example 1: Two positive charges, each 4. 18 ? C, and a negative charge, -6. 36 ? C, are fixed at the vertices of an equilateral triangle of side 13. 0 cm. Find the electrostatic force on the negative charge. | F = Q1Q2 / 4 or2= (8. 99 x 109) [(4. 18 x 10-6)(6. 6 x 10-6) / (13. 0 x 10-2)2]= 14. 1 N (Note: negative sign for -6. 36 ? C has been ignored in the calculation)FR = 2 x Fcos300= 24. 4 N, vertically upwards| Electric field strength due to a Point Charge Q : E = Q / 4 or2 {NB: Do NOT substitute a negative Q with its negative sign in calculations! } Example 2: In the figure below, determine the point (other than at infinity) at which the total electric field strength is zero. From t he diagram, it can be observed that the point where E is zero lies on a straight line where the charges lie, to the left of the -2. 5 ? C charge. Let this point be a distance r from the left charge.Since the total electric field strength is zero, E6? = E-2? [6? / (1 + r)2] / 4 or2 = [2. 5? / r2] / 4 or2 (Note: negative sign for -2. 5 ? C has been ignored here) 6 / (1 + r)2 = 2. 5 / r2 v(6r) = 2. 5 (1 + r) r = 1. 82 m The point lies on a straight line where the charges lie, 1. 82 m to the left of the -2. 5 ? C charge. Uniform electric field between 2 Charged Parallel Plates: E = Vd, d: perpendicular dist between the plates, V: potential difference between plates Path of charge moving at 90 ° to electric field: parabolic. Beyond the pt where it exits the field, the path is a straight line, at a tangent to the parabola at exit.Example 3: An electron (m = 9. 11 x 10-31 kg; q = -1. 6 x 10-19 C) moving with a speed of 1. 5 x 107 ms-1, enters a region between 2 parallel plates, which are 20 mm apart and 60 mm long. The top plate is at a potential of 80 V relative to the lower plate. Determine the angle through which the electron has been deflected as a result of passing through the plates. Time taken for the electron to travel 60 mm horizontally = Distance / Speed = 60 x 10-3 / 1. 5 x 107 = 4 x 10-9 s E = V / d = 80 / 20 x 10-3 = 4000 V m-1 a = F / m = eE / m = (1. 6 x 10-19)(4000) / (9. 1 x 10-31) = 7. 0 x 1014 ms-2 vy = uy + at = 0 + (7. x 1014)( 4 x 10-9) = 2. 8 x 106 ms-1 tan ? = vy / vx = 2. 8 x 106 / 1. 5 x 107 = 0. 187 Therefore ? = 10. 6 ° Effect of a uniform electric field on the motion of charged particles * Equipotential surface: a surface where the electric potential is constant * Potential gradient = 0, ie E along surface = 0 } * Hence no work is done when a charge is moved along this surface. { W=QV, V=0 } * Electric field lines must meet this surface at right angles. * {If the field lines are not at 90 ° to it, it would imply that there is a non- zero component of E along the surface. This would contradict the fact that E along an equipotential = 0. Electric potential at a point: is defined as the work done in moving a unit positive charge from infinity to that point, { a scalar; unit: V } ie V = W / Q The electric potential at infinity is defined as zero. At any other point, it may be positive or negative depending on the sign of Q that sets up the field. {Contrast gravitational potential. } Relation between E and V: E = – dV / dr i. e. The electric field strength at a pt is numerically equal to the potential gradient at that pt. NB: Electric field lines point in direction of decreasing potential {ie from high to low pot}.Electric potential energy U of a charge Q at a pt where the potential is V: U = QV Work done W on a charge Q in moving it across a pd ? V: W = Q ? V Electric Potential due to a point charge Q : V = Q / 4 or {NB: Substitute Q with its sign} Electromagnetism When a conductor carrying a current is plac ed in a magnetic field, it experiences a magnetic force. The figure above shows a wire of length L carrying a current I and lying in a magnetic field of flux density B. Suppose the angle between the current I and the field B is ? , the magnitude of the force F on the conductor is iven by F = BILsin? The direction of the force can be found using Fleming? s Left Hand Rule (see figure above). Note that the force is always perpendicular to the plane containing both the current I and the magnetic field B. * If the wire is parallel to the field lines, then ? = 0 °, and F = 0. (No magnetic force acts on the wire) * If the wire is at right angles to the field lines, then ? = 90 °, and the magnetic force acting on the wire would be maximum (F = BIL) Example The 3 diagrams below each show a magnetic field of flux density 2 T that lies in the plane of the page.In each case, a current I of 10 A is directed as shown. Use Fleming's Left Hand Rule to predict the directions of the forces and wo rk out the magnitude of the forces on a 0. 5 m length of wire that carries the current. (Assume the horizontal is the current) | | | F = BIL sin? = 2 x 10 x 0. 5 x sin90 = 10 N| F = BIL sin? = 2 x 10 x 0. 5 x sin60 = 8. 66 N| F = BIL sin ? = 2 x 10 x 0. 5 x sin180 = 0 N| Magnetic flux density B is defined as the force acting per unit current in a wire of unit length at right-angles to the field B = F / ILsin ? > F = B I L sin ? {? Angle between the B and L} {NB: write down the above defining equation & define each symbol if you're not able to give the â€Å"statement form†. } Direction of the magnetic force is always perpendicular to the plane containing the current I and B {even if ? ? 0} The Tesla is defined as the magnetic flux density of a magnetic field that causes a force of one newton to act on a current of one ampere in a wire of length one metre which is perpendicular to the magnetic field. By the Principle of moments, Clockwise moments = Anticlockwise moments mg â⠂¬ ¢ x = F †¢ y = BILsin90 †¢ yB = mgx / ILy Example A 100-turn rectangular coil 6. 0 cm by 4. 0 cm is pivoted about a horizontal axis as shown below. A horizontal uniform magnetic field of direction perpendicular to the axis of the coil passes through the coil. Initially, no mass is placed on the pan and the arm is kept horizontal by adjusting the counter-weight. When a current of 0. 50 A flows through the coil, equilibrium is restored by placing a 50 mg mass on the pan, 8. 0 cm from the pivot. Determine the magnitude of the magnetic flux density and the direction of the current in the coil.Taking moments about the pivot, sum of Anti-clockwise moments = Clockwise moment (2 x n)(FB) x P = W x Q (2 x n)(B I L) x P = m g x Q, where n: no. of wires on each side of the coil (2 x 100)(B x 0. 5 x 0. 06) x 0. 02 = 50 x 10