Uma fonte puntiforme produz ondas mecânicas esféricas em um meio tridimensional uniforme e isotrópico.

A intensidade da onda (I) é dada pela razão entre a potência irradiada e a área da superfície da frente de onda. Considerando-se que a potência “P” da fonte é distribuída uniformemente na superfície da frente de onda, a intensidade “I” em um ponto situado a uma distância “d” da fonte é dada pela expressão:

Considerando a figura e que !$ \sin 75º !$ é igual a !$ \large{\sqrt2+\sqrt6 \over 4} !$, calcula-se que !$ a=5 !$ (    )cm.

Se !$ \sin (a+b)=- \large{1 \over 2} !$ e !$ \cos (a-b)=-\large{\sqrt3 \over 2} !$, então o valor de !$ (\sin \, a+ \cos \, a) (\sin \, b + \cos \, b) !$ !$ (\sin b + \cos \, b) !$é

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Oil contaminating Brazil’s beaches very likely from Venezuela

Anna Jean Kaiser

Thick crude oil that has stained hundreds of miles of pristine Brazilian beach in recent weeks probably originated in Venezuela, the Brazilian government has said, in an accusation likely to further strain relations between the two countries.

Brazilians authorities have been investigating the growing disaster for more than a month, as the oil has spread to more than 130 beaches across nine states.

Ricardo Salles, the country’s environment minister, told that a study by Petrobrás had concluded that the oil “is very likely from Venezuela. He said that a foreign ship near Brazil’s coastline appeared to have caused the spill.

There was no immediate response from Venezuela.

Social media users have shared shocking images of the spill, showing kilometers of white sand stained with oil blotches and dead, oil-covered turtles and dolphins. One shows thick black oil lapping up against a rocky jetty.

Adapted from The Guardian.

According to the text, we can infer that .

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All of me

John Legend

‘Cause all of me
Loves all of you
Love your curves and all your edges
All your perfect imperfections
Give your all to me
I’ll give my all to you
You’re my end and my beginning
Even when I lose I’m winning
‘Cause I give you all of me
And you give me all of you
...

A synonym for the word “edges” is:

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Paul Thompson is a student and he has a part-time job, too. He lives in London and goes to university there. Paul works at an Italian restaurant called Mamma Mia. He’s a waiter there. He likes his job very much, but he doesn’t like to work on the weekends. When he is free, he likes to go to the movies. He recently watched “Avengers - Infinity War”, a superhero movie that was a huge success.

Change the sentence into the interrogative form.

“The cost of living has doubled in relative terms over recent years.”

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Many advertisements also contain a slogan or a to attract the consumer’s attention. Effective slogans are usually short, easy to remember and to repeat. Another technique for advertising is commercials. It’s when a person, often a famous one, shows up in ads and commercials. They speak on behalf of a product and they promote from hygiene items to financial institutions. Sponsors pay high to these “posters boys” because it’s been proved that celebrities are a status symbol that not only play a role model but can easily influence people.

Adapted from Grad Two.

Choose the best alternative to complete the text subsequently.

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Can you recognize your emotions?

If I ask you how you are feeling, you may answer: “I’m feeling good, I’m fine”! But what does that “good” or “fine” really mean? Would it mean fascinated, curious, balanced, joyful, encouraged, hopeful, motivated, happy?

On the other hand you might also reply: “I’m feeling bad”, and, then, recognize that you are feeling bored, lonely, sorry, anxious, fearful, nervous, insecure or frustrated.

The advantage of making such distinctions, rather than feeling “good” or “bad” is that your emotions indicate what you need to do to feel more satisfying.

For example, if you are angry with a person, you can argue with him, you can request him to stop his offensive behavior or you can avoid him. You have choices. Recognize each of your emotions and pay attention to what they are communicating to you.

Adapted from Inglês no mundo do trabalho.

According to the text, we can infer that .

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Corruption

People all over the world complain about the corruption of police, government officials, and business leader. Three examples of corruption are:

• a police officer takes money from a driver so he doesn’t give the driver a ticket for speeding.

• a public official gives a government contract to a company in which he, or she has a financial interest.

• a company that wants to do business with a government agency offers public official money, or a gift to choose that company for the job.

Some people feel that power promotes corruption and that corruption is just an unavoidable part of human nature. But everyone agrees that it’s a terrible problem all over the world.

Adapted from Top Noch.

According to the text, the underlined word “which” is a .

No gráfico da figura a seguir tem-se a intensidade da força (F), em newtons, em função do tempo (t), em segundos. Nesse gráfico, a força, que é a resultante das forças exercidas sobre o corpo de massa m tem direção constante. Sabendo que no instante t = 0 o corpo está em repouso, determine o valor do impulso da força, em N.s, sobre o corpo, somente, no intervalo de 0 a 4 segundos.