The U2 was one of _____ military planes of the Cold War. It was designed to fly high over a foreign country, take pictures and gather information.

The U2 was built in Area 51, a secret place in Nevada, known for UFO sightings. The US Air Force built the area to create such a secret plane and test new weapons.

The single-pilot plane could fly at an altitude of over 20 km above the earth's surface. With its special cameras it could take detailed photos and close-ups of objects on the ground. Today, the US Air Force still operates a modified version of the U2, however it is not used as a spy plane any more. Current planes have a larger fuselage and need less fuel than their predecessors of the Cold War. They are also equipped with more sophisticated instruments. Some of them fly over Afghanistan and support American soldiers on the ground. They also saw action during the Gulf War and the conflict in the Balkans.

U2s are also used for research. NASA uses the former spy planes for tests in the atmosphere.

(adapted from http://www.english-online.at/news-articles/history/u2-spy)

Choose the correct alternative to complete the article.

Why do planes crash?

Navigational errors are among the most common causes of plane crashes. Planes are flown into a mountain or the sea out of a variety of reasons. Sometimes weather conditions are bad, in other cases pilots have made bad judgements.

In 1996 a Peruvian airliner crashed into the sea after the computer stopped working. The crew had almost no data left to work with and didn't know at which height they were flying when they hit the water.

In 1977 almost 600 people got killed when two planes were heading at full speed towards each other and collided in heavy fog on the runway in Tenerife. The crash happened after planes had been guided to Tenerife because Gran Canary airport was closed.

In June 2009 an Air France airbus disappeared off the coast of Brazil. Although the wreckage was found after a few days it took investigators almost three years to find out what had really happened to the plane.

Pilots are criticising the way planes are ____. In the past decades the structure of planes has changed. More computers and automated systems are taking over, the pilot often has no alternatives left.

(Adapted from http://www.english.online.at/news-articles/technology)

Complete the sentence in the text with the correct option

Choose the alternative that contains the right use of the relative pronoun, in order to write the two sentences below as a single sentence:

That is the teacher. I spoke to her about my grades.

Um aparelho continha as seguintes especificações de trabalho: Entrada 9 V – 500 mA. A única fonte para ligar o aparelho era de 12 V. Um cidadão fez a seguinte ligação para não danificar o aparelho ligado à fonte:

Considerando a corrente do circuito igual a 500 mA, qual deve ser o valor da resistência R, em !$ Ω !$ , para que o aparelho não seja danificado?

A pilot from Northwest Airlines flight was less than pleased with the food which was to be served on the flight. He decided to find some better food, so he left his aeroplane, and then left the airport to find food even though he had a plane to fly. The passengers were left to wait 90 minutes until the pilot came back and when the pilot came back he was fired on the spot for “abandoning his plane”.

(Adapted from www.flightglobal.com)

According to the text, all the alternatives are true, except:

Um corpo está submetido à ação de duas forças com intensidades 5 N e 4 N, respectivamente, que formam entre si, um ângulo de 60°. O módulo da força resultante que atua sobre o corpo será

Sobre uma mesa sem atrito, um objeto sofre a ação de duas forças !$ F_1 !$ = 9 N e !$ F_2 !$ = 15 N, que estão dispostas de modo a formar entre si um ângulo de 120o. A intensidade da força resultante, em newtons, será de

Em um campeonato de tênis estão inscritos 10 militares. Para disputar o campeonato, esses militares podem formar_______duplas diferentes.

Did you remember it’s April Fools Day today? My sister loves playing jokes. At breakfast, she said, “Robert and I ____ going to elope! We’re going to Robben Island. It’s the place where Nelson Mandela was in prison. My guidebook say it is a “place forever connected with the fight for freedom”. So, if you receive a phone call today about winning the lottery or something, don’t get excited. It’s probably an April Fools joke.

(taken from Stories worth reading)

GLOSSARY

to elope: fugir de casa secretamente para se casar.

The sentence “We’re going to Robben Island”, in the text, refers to the

Se !$ f(x) = { \large x - 1 \over x + 1} + { \large 3x \over \sqrt{x + 4}} !$ é uma função, seu domínio é D = {x !$ ∈ !$ !$ \Re !$ / __________}.