The resistance of a wire varies with its length Essay Example for Free

The resistance of a wire varies with its length Essay To investigate how the resistance of a wire varies with its length Equipment Needed: o power pack o 5 wires o Voltmeter o Length of wire o Ruler o Ammeter o Crocodile clip Circuit Diagram: Prediction: The equation V=IxR is how you find the resistance rate. Im now going to re-arrange it to R= V for this to work the temperature has to stay I Constant or it will not work. So I predict that if I increased the length of the wire the resistance will be increased. So I think that if you double the length of the wire the resistance will be doubled. Method: o Collect the equipment and set up the circuit by measuring the wire o Turn on the power pack. o Slowly increase the power o Connect the crocodile clip onto the copper wire to make the circuit complete. o Using a ammeter to measure the amount of current in the circuit o Using a voltmeter to measure the amount of voltage across the circuit o Record results Repeat this with all the different lengths on the wire. Also on the experiment make sure that you read the meter from directly in front by using parallax. Another thing makes sure that the needle is not moving around this then makes the measurement correct. Fair Test: To make this a fair test Im going to keep everything the same in each test apart from the length of wire. The wire will be the same thickness and material every time. Safety: Its important that the wire does not get to hot that it burns. To prevent this from happening I wont let the current go any higher than 2amps. Preliminary work: Current (A) Measurement (CM) Voltage (V) 2. 0A 10CM 0. 4 1. 5A 10CM 0. 3 1A 10CM 0. 2 0. 5A 10CM 0. 1 Current (A) Measurement(CM) Voltage(V) 2. 0A 90CM Off scale 1. 5A 90CM 3. 4 1. 0A 90CM 2. 5 0. 5A 90CM 1. 0 We decided not to use a current of 2 Amps because it melts the wire. The other thing was we decided not use 90CM because one of the readings was off the scale. Practical Results: Length (CM). Current (A) Voltage (V) Corrected Resistance ( ) CorrectedLength (CM) Current (A) Voltage (V) Corrected Resistance ( ) Corrected Length (CM) Current (A) Voltage (V) Corrected Resistance ( ) Corrected   Our meter read 0. 1V even when no circuit was connected so I had to take this reading off all the results which is why there is a corrected column. Length (CM) Average resistance (ohms) Conclusion: I have noticed that as the length of the wire increases the resistance also increases. This happens because: This all happens because the resistance has doubled like I said in my prediction. I checked this by looking on my graph E. g. 20CM= 0. 44 40CM=0. 88 80CM=1. 76 See each time it has doubled. Evaluation: We found out that there was an error in our voltmeter which meant our first point was on 0. 1. This made our results incorrect which meant we had to re calculate the numbers. We read all our results to one decimal point instead of two. I have an Anomalous point at 20cm. I can see from my results there was a error at 15amps. If I ignore this result and take an average of 0. 5+1. 0amps I get a point that lies on my line. I have shown this on my graph in red. This error accrued by reading the metre wrong. Holly Atkins Page: Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.

Presidential Biography of Theodore Roosevelt :: American Presidents History Governmental Essays

Presidential Biography of Theodore Roosevelt Ascension To The White House As Governor of New York, Roosevelt would once againl stand on his own and distance himself from the political bosses and machines that got him elected. The head of the Republican machine, Thomas Platt, had misgivings about making Roosevelt governor of New York because of Roosevelt's total independence and his reform nature. But in the gubernatorial race of 1898, with the bad press the Republican Party was receiving, there seemed to be no one else who had a chance. Roosevelt was riding the crest of the wave of being a true war hero, and with Platt's help together they might keep the Democrats from winning the office. Platt in return for his help expected Roosevelt to let him make the appointments and carry the party line. Roosevelt had no intentions of being Platt's puppet, and as soon as he got in office the two would begin to battle. Roosevelt had to be careful, because to totally alienate Platt would cripple his chances to go any further politically or even threaten his chances to be reelected governor. Roosevelt made his point by declining to appoint Platt's first suggested appointee. After making his point, however, Roosevelt tried to work with the Republican boss to the extent of not abandoning his own principals. Platt for his part could not toss the war hero out on his ear in 1900, but at the same time, he wanted to find a way to gracefully get Roosevelt out of his hair. Platt's opportunity to get rid of Roosevelt came with the approach of the presidential election of 1900. McKinley was discretely looking for a new running mate to replace Hobart in the upcoming election. It was fairly obvious that the Democrats would choose William Jennings Bryan as their candidate of choice again, and McKinley would need a fiery speaking running mate to offset Bryan's oratory abilities. McKinley would simply sit back and look Presidential while his running mate would attack Bryan. Hobart was not a gifted orator, and this decision to replace him became all that much easier when he died just prior to the national Republican convention. Mark Hanna had run McKinley's campaign in 1896 and wanted nothing to do with Roosevelt in 1900. Platt on the other hand saw his opportunity to get rid of Roosevelt at the same time saving face in his own home state of New York.

Diplomatic History Essay

Operation Rolling Thunder refers to an intense onslaught carried out by the United States against the North Vietnamese in the period between 1965-1968. The rationale behind this attack was not clear, as even its chief architects believe it was not clear-cut. No one had put into consideration the political costs and loss of lives. President Johnson hoped that with this onslaught, he would boost the dying morale of the southern Vietnamese by impressing upon them the Americans might. This however achieved the opposite by diminishing his political standing at home and did not help to bring the North Vietnamese to the negotiating table as was hoped. The Six-Day War is a war that pitted Israel on one side against Jordan, Egypt and Syria. These countries had vowed not to recognize the legitimacy of Israel and wanted it destroyed, however Israel victory dealt these countries a huge blow and they retreated after it became apparent that Israel would reach their capital. This war brought a near clash between two superpowers then, the United States and the Soviet Union, with the U. S behind Israel and USSR behind the Arab states. This war had put the U. S in a tight spot as it did not want to sour its relations with the Arabs or its diplomatic ties with Israel. This is seen as the reason why the U. S exercised restrain and only aided Israel with weapons but no direct intervention. The Iran Contra Scandal occurred in 1987 and refers to a deal entered into by president Reagan’s administration and Iran. The United States was to supply Iran with weapons so that it would facilitate and press for the release of American hostages held by the Hezbollah. This scandal tarnished the U. S stand abroad of not negotiating with terrorists and also led to the plummeting of Reagan’s popularity. It would also see the conviction of some high-ranking officials. Mikhail Sergeyevich Gorbachev of Russia was the last president of the United Soviet Socialist Republic before it collapsed in 1991. He is hailed for having initiated the move that led to the end of cold war. He introduced reforms in Russia and tightened the relations with President Ronald Regan, ending the cold war and consequently the breaking up the USSR. It is during this tenure that the relations between the USSR and the U. S were improved. Core to his reforms was re-introduction of ties with the west. Kosovo, Yugoslavia, had been rocked by fighting between Albania guerillas and Serb forces. The United States and NATO forces stepped in to help quell the fighting resulting to what came to be known as Operation Allied Forces that initiated an onslaught against Serbia till Slobodan Milosevic withdrew from Kosovo. The United States over the years was actively involved in the process meant to restore peace although the congress did not expressly authorize the air strikes nor block them. To date The UN Resolution 1244 has failed to establish the status of Kosovo. The United States has been supporting what is referred to as the Ahtisaari plan that seeks to have Kosovo supervised. Russia is opposing the plan and vows to use the Veto power should the situation demand. The Dayton Accords refer to the peace agreements that saw the end of the Bosnia war in 1995. This agreement was the culmination of a series of negotiations that had before been unfruitful. The United States and Russia had been mounting pressure for the warring sides to accept negotiations. These negotiations held in Ohio brought together a cross section of leaders from the region. This was done under the tutelage of the U. S secretary of state Warren Christopher together with the representatives of European Union. The Official peace pact was to be signed in France by Clinton, John Major, and Jacques Chirac amongst others. This pact was to see the international community lead the implementation of the treaty backed by the NATO forces. Ngo Dinh Diem was born in 1901. He went to the United States due to political turmoil at home. In the US he would meet the then influential leaders where he reiterated his opposition to colonialism and communism in his bid to gain their approval. He succeeded and the United States installed him as the president hoping he would become a U. S puppet. This however did not happen and he was oppressive of the Southern Vietnamese. He rigged the elections that were to follow and imprisoned opposition leaders and critics. The United States was torn between a rock and a hard place, it risked being stuck with an unpopular leader who was unable to unite Vietnam and in turn lose the country to the communists. This is what led CIA to sanction a plot to have Diem assassinated by failing to offer the protection they were giving him before. Consequently he was assassinated in 1963 and his place taken by Nguyen Van Thieu. The relationship between the United States and PLO can only be described as that of perpetual hostility towards each other. To the United States, PLO represented a major threat to its interests and ally in Middle East. PLO also saw the U. S as a threat and that is why it aligned itself with the USSR and took a strong anti-American stance. In spite of this standoff, the United States initiated a dialogue between the two in 1988. PLO accepted the status of Israel and agreed to denounce terrorism hence triggering the dialogue. All along there had been a long stand-off between the two as PLO had refused to acknowledge the existence of Israel while in turn the U. S had not recognized PLO as the voice of the Palestine people. By accepting to negotiate with the PLO, PLO saw this as a form of recognition and it felt that it had won against the U. S’ hard stance. The U. S stand against PLO and the initiation of the talks has always been a defining moment in Middle East because it gave an international recognition, in line with the UN resolutions, a nation it considered a terrorist movement. The Strategic Defense Initiative (SDI) fronted by President Reagan, aimed at developing a system that would use ground and space systems to defend the United States in case of a nuclear ballistic missiles attack. This system did not succeed as it was intended to, but it is hailed as being the basis under which the current anti-ballistic missiles were made. All these efforts and research was put under the Strategic Defense Initiative Organization that was brought together in 1984 to oversee all matters relating to missile defense. The Taliban are a Sunni Islamic movement that was at the helm of leadership in Afghanistan for a period of five years up to 2001 when they were removed from power by a coalition of forces led by the united states. It has a rather interesting history as in its early days it was supported by the United States to fight off the communists who wanted to take over Afghanistan. After taking over power in 1998, the Taliban hard stance, Sharia law, suppression and persecutions did not endear it to many countries including the United States which saw it as harboring terrorists such as the Al Qaeda. It was ousted from power by a coalition of forces and the Northern alliance in what came to be known as war on terror. Part 2 President Richard Nixon and Henry Kissinger remain the two of the most important figures in the United States as far as foreign policy is concerned. No doubt that Nixon’s administration was riddled with a scandal that would lead to his resignation. Critics agree however that his tenure was not without some important accomplishments. Appropriately President Nixon came into power when the cold war had intensified and the world was at the brink of war with the United States and the Soviet Union rocked into a perpetual duel that was threatening a peaceful co-existence between the West and East. President Nixon was elected on a platform of ending American forces engagement in Vietnam. This, he achieved although his withdrawal was rather slow much to the consternation of many Americans. It had seemed that Nixon rather believed that he could correct the mess he had inherited in Vietnam, snatch victory and withdraw the troops honorably. This however did not happen and the events that followed remain his lowest moments in leadership. Nixon and Kissinger were advocating a foreign policy that would see the United States pursue an effort to limit the expansion of the Soviet bloc influence, support militarily and economically any governments that would aid their course whether or not such governments were repressive or had poor ratings as far as civil rights are concerned. This would explain why this tenure was characterized by overthrowal from power popularly elected regimes and supplanting them with dictatorial leaderships. Iran and Chile serves as good attestation to this. The key objective of Nixon administration was to keep communism in check at whatever cost even if it meant trampling on the civil rights of the citizens and dropping hundreds of bombs. The Vietnam War still remains the biggest to both Kissinger and Nixon’s profiles. Faced with growing opposition and plummeting opinion ratings, Nixon remained aloof and initiated attacks in Vietnam while hoodwinking the American public by withdrawing the forces bits by bits. To his administration ‘place with honor’ remained the key strategy. It is Detente that remains the hallmark of his achievements, on top of his ability to limit and finally withdraw American forces from Vietnam. In Detente he promised to ease relations with the former archrivals of America. It was a new type of diplomacy that would see a permanent relaxation of relations between the superpowers, even the nations that were perceived as enemies before. This, he accomplished by improving the relations between the United States and China. Kissinger was Nixon’s key operative. He was highly secretive to the extent that his meeting with Chinese officials was unknown to the ambassador of the U. S to China, George Bush snr. However he was able to improve the sour relation that existed. This was in the Nixon’s bid to woo China after it had fallen out with the Soviet bloc and consequently tilt the balance to his advantage. Aided by the Kissinger, Nixon introduced what was referred to as the Nixon Doctrine; this is what formed the basis of his foreign policy. The United States, to maintain its influence would provide military support to its allies but not in any way provide troops. In wooing China, Nixon and Kissinger who were realists, had reconciled that China was far much important to be ignored in the international scene being the most populous. This also gave impetus to his re-election bid especially as the Ping Pong diplomacy had drawn a perception that he identified with the common voter. Through the Strategic Arms Limitation Treaty of 1972 (SALT), the United States and the Soviet Union agreed to curtail further production of high range ballistic missiles as well as their defense systems. This ‘strategic parity’, as many scholars refer to it, was to be a substitute to the arms race. The Soviet bloc agreed to this immediately probably fearing the improved relations between China and the United States. To wrap up Nixon achievements in foreign policy was his visit to China, where he became the first president to do so; this had privately been arranged by Kissinger. He also went to Moscow where he and Brezhner signed the SALT and trade agreements. The shuttle diplomacy also said off relatively where Henry Kissinger was able to broker a peace deal with Israel an Arab in the Yom Kippur war. In this war the U. S had been torn between a rock and a hard place. It sought to protect Israel and did not want to scuttle its friendship with the Arab states. Although Nixon had the above achievements, his mistakes or miscalculations further outweighed the accomplishments. Many people in U. S and internationally remember him for his misdeeds more that these achievements. His administration single handedly put the image of the United States as a champion of civil rights and peace into disrepute. To start with was his handling of the Vietnam War. He was unable to come to terms with the fact that the United States could lose the war and was willing to put the lives of American soldiers on the line to drive this point home, but to no avail. Despite cutting his stature in the international limelight as a statesman by establishing ties with china, the question of Vietnam is still very troublesome to both Nixon and Kissinger. Nixon had vowed to win peace. Vietnamization or the concerted attack in Laos and Cambodia put a permanent dent on his reputation. He hoped that these would paint an image of a ‘madman’ and compel Hanoi to reach a favorable agreement. These attacks prompted Americans to take to the streets in protest especially as it became apparent that he had dropped all pretext of diplomacy. Although Kissinger was able to bring the warring parties into negotiations, the terms were not any different from the ones that north Vietnam had brought to the table in 1969, an indication that all those years of attack and loss of lives had not borne fruits especially to the United States. It is the Watergate scandal however that broke the camels back and forced Nixon out of office. The Watergate scandal remains the greatest evidence of the atrocities committed by the United States where both Kissinger and Nixon undermined democracy in the third world and brought bloodshed. It is these atrocities that led to calls by civil and human rights activists to have Kissinger investigated for crimes against humanity. After the scandal, the United States was not credible in its self-proclaimed international role. Oil crises would loom in the U. S as the Middle East placed embargoes. There was also a political re-alignment with disillusionment characterizing the Republican Party. Kissinger however was left unscathed and went on to serve as the secretary of state in Ford and Carters administration. Nixon’s presidency is a tenure that many Americans would wish to put behind.

Use of Estar and Ser with Adjectives of Marital Status

If you are learning to speak Spanish, you may be wondering which word describing martial status is correct — soy casada or estoy casada? The quick answer is that theyre both correct! With adjectives of marital status — ones other than casado (married) include soltero (single), divorciado (divorced) and viudo (widowed), along with their feminine equivalents — estar and ser are more or less interchangeable. Difference Between Ser and Ester Although the differences between ser and estar are usually distinct, that just doesnt seem to be so with the adjectives of marital status, where youll often hear the two verbs used with little difference in meaning. In some areas, however, one or the other may be preferred, and estar probably has an edge in everyday speech, at least with casado. Even so, use of estar can suggest (but doesnt always) there has been a change in marital status. Thus, you might ask a new acquaintance  ¿es usted casado? if you see his marital status as part of his identity. But you might ask a friend you havent seen for a while  ¿està ¡s casado? as a way of asking, Have you become married since I saw you last? or Are you still married? Similarities With Other Spanish Adjectives The same is true with very few adjectives, such as gordo (fat) and delgado (thin), that describe personal characteristics. Both es gordo and està ¡ gordo can be used to say he is fat, for example. The latter often suggests that there has been a change, while the former may suggest merely a description of the way a person is. So the choice of verb can suggest an attitude — estar may suggest a state of being at the moment, while ser may suggest an inherent characteristic. In fact, that is the safest way to make your verb choice, and estar must be used where indeed there has been a change. But in everyday descriptions, the distinction of meaning isnt always a sharply clear one.