O centro de massa de um sistema de duas partículas se desloca no espaço com uma aceleração constante !$ \vec{a} = 4,0 \hat{i} + 3,0 \hat{j} (m/ s^2) !$ . Num dado instante t, o centro de massa desse sistema está sobre a reta y=5,0m com uma velocidade !$ \vec{v} = 4,0 \hat{i} (m/s) !$, sendo que uma das partículas está sobre a origem e a outra, que possui massa de 1,5kg, encontra-se na posição !$ \vec{r} = 3,0 \hat{i} + 8,0 \hat{j} (m) !$. Quanto valem, respectivamente, o módulo da quantidade de movimento do sistema no instante t, e o módulo da resultante das forças externas que atuam no sistema?

Choose the best reply to this statement.

Mary: l have alI the books the teacher told us about last class.

You: (1).

Read the text below. Why was this Army soldier in eastern Afghanistan praised by the Defense Secretary?

GATES HAILS SOLDIER SNAPPED IN PINK BOXER SHORTS

Defense Secretary Robert Gates on Thursday praised an Army soldier in eastern Afghanistan who drew media attention this month after rushing to defend his post from attack while wearing pink boxe r shorts and flip-flops, Reuters reported. Gates said in prepared remarks that he wants to meet the soldier and shake his hand the next time he visits Afghanistan.

"Any soldier who goes in to battle against the Taliban in pink boxers and flip-flops has a special kind of courage," Gates said in a speech to be delivered in New York. "I can only wonder about the impact on the Taliban. Just imagine seeing that: a guy in pink boxers and flip-flops has you in his cross-hairs. What an incredible innovation in psychological warfare, " he said.

Army Specialist Zachary Boyd, 19, of Fort Worth, Texas, rushed from his sleeping quarters on May 11 to join fellow platoon members at a base in Afghanistan's Kunar Province after the unit came under fire from Taliban positions. A news photographer was on hand to record the image of Boyd standing at a makeshift rampart in helmet, body armor, red T-shirt and boxers emblazoned with the message: "I love NY". When the image wound up on the front page of the New York Times, Boyd told his parents he might lose his job if President Obama saw him out of uniforrn.

(Adapted from http://www.foxnews.com/story/O. 2933, 521138 f 00. html)

This Army soldier in eastern Afghanistan was praised by the Defense Secretary ...

O raio de uma esfera em dm é igual à posição ocupada pelo termo independente de X no desenvolvimento de !$ { \begin{pmatrix} 25^{ { \large 1 \over 2} { \begin{pmatrix} sen^2 { \large \times \over 2} \end{pmatrix}}} + 5^{ ( 1 + cos\,\times)} \end{pmatrix}}^{54} !$ quando consideramos as potências de expoentes decrescentes de !$ 25^{ { \large 1 \over 2} { \begin{pmatrix} sen^2 { \large \times \over 2} \end{pmatrix}}} !$. Quanto mede a área da superfície da esfera?

Which of the alternatives below completes the sentence correctly?

Juliet and Romeo in the balcony scene: "Oh, Romeo, if my brother (1) us together, certainly he (2) you.

Please, go away now."

Which of the alternatives below completes the sentence correctly?

(1) will it take you to finish the project? More than a week?

Which sequence best completes the text below?

When we go out on weekends, I don't mind (1). I enjoy (2) by car because it is more comfortable and I can't resist (3) to take photos. However, I avoid (4) at night as I prefer not (5) the risk of (6) on the wheel.

Based on the text below, answer question.

CLlMATE CHANGE WILL DESTROY US

Climate change over the next 20 years could result in a global catastrophe costing millions of lives in wars and natural disasters.

A secret report, suppressed by US defense chiefs and obtained by The Observer, warns that major European cities will be sunk beneath rising seas as Britain is plunged into a 'Siberian' climate by 2020. Nuclear conflict, mega-droughts, famine and widespread rioting will erupt across the world.

The document predicts that abrupt climate change could bring the planet to the edge of anarchy as countries develop a nuclear threat to defend and se cure dwindling food, water and energy supplies. The threat to global stability vastly eclipses that of terrorism, say the few experts privy to its contents.

'Disruption and conflict will be endemic features of life,' concludes the Pentagon analysis. 'Once again, warfare would define human life.'

(Adapted from http://www.guardian.co.uk/climatechange/story/0.12374.1153530,00.html)

According to the text above, what will be the result of climate change?

Which sequence best completes the text below?

HOW TO GET OFF THE B-SCHOOL WAIT LIST

Every school has a different policy about whether you should be in touch with (1). Some say outright don't call (2), we'll call (3). If (4) is one of (5), follow those instructions. Disobeying will most likely do more harm than good.

(Adapted from http://www.1.íorbes.com)

Which sequence best completes the text below?

WHY 80 MANY BOOKS?

Conventional wisdom among college and uni versi ty students (and many of their parents) in early 2007 is that "everything needed for research is available free on the Web." Therefore, academic libraries are often viewed as costly dinosaursunnecessary expenses in today's environment. This idea is uninformed at best and foolish at worst. If college and university libraries and librarians (1) , we (2) to invent, better yet, re-invent them.

(Adapted f.roro http://www.educause.edu)