Duas polias estão acopladas por uma correia que não desliza. Sabendo-se que o raio da polia menor é de 20 cm e sua frequência de rotação !$ f_1 !$ é de 3600 rpm, qual é a frequência de rotação !$ f_2 !$ da polia maior, em rpm, cujo raio vale 50 cm?

Should we fear that someday a huge asteroid would fulfill one of the apocalyptic scenarios envisaged for Earth, when a space rock smashes into our planet causing a global disaster? Judit Gyorgyey-Ries, an experienced astronomer at the University of Texas’ McDonald Observatory becalms the worried doomsdayers with a scientific approach to the matter. In an interview with astrowatch.net, she discusses potential asteroid threats, her current research and misinterpretation of her words by tabloid newspapers.

Taken from www.spacedaily.com/Deep_Impact.html

In the text, the meaning of “misinterpretation”is to

Thomas Edison tried two thousand different materials in search of a filament for the light bulb. When none worked satisfactorily, his assistant complained, “All our work is in vain. We have learned nothing.”

Edison replied very confidently, “Oh, we have come a long way and we have learned a lot. We know that there are two thousand elements which we cannot use to make a good light bulb.”

(Adapted from academictips.org)

The sentence “We have learned nothing”, in the text, can be replaced by

Choose the alternative that does not complete the sentence below.

It is possible to pass an exam, you study hard.

Marque a alternativa correta quanto às regras de regência verbal do verbo “bater”.

In the sentence “Maria learns fast”, the word “fast”, in bold type, is

Why study abroad?

Have you considered studying abroad, but are not sure whether it’s worth your time? If you ask anybody who has studied abroad, he or she will most certainly tell you that it is a life-changing experience and one of the most rewarding things he or she has ever done. Perhaps you’re not certain what benefits you can reap from an extended stay in a foreign country. There are many reasons why you should take the plunge.

Adapted from www.vistawide.com.

According to the text, studying abroad

Dois garotos decidem brincar de gangorra usando uma prancha de madeira de massa igual a 30 kg e 4 metros de comprimento, sobre um apoio, conforme mostra a figura.

Sabendo que um dos garotos tem 60 kg e o outro 10 kg, qual a distância, em metros, do apoio à extremidade em que está o garoto de maior massa?

Dada a reta r: 2x – 3y + 5 = 0 e o ponto P(5, 6), a distância de P à reta r é