<p>I’m making them up. But, I’m sure there’s a book somewhere with something similar to each of these questions. Then again, not sure where else you’d find that pigeons one :)</p>
<p>For the pigeon question: It’s tempting to say E but that’s not the answer. But in a close object kind of thing everything is measured inside it. Mediums can be measured. (like water) Air is a medium so the mass of it is often neglected. </p>
<p>Anyways It would be 9.81 * 22 = 215.82. Round up to 220N and it would be D.</p>
<p>I think it’s E. We do not know if the pigeons are able to actually lift up the cage off of the scale. If they are, the weight (normal force) will be shown to be less than 200 N. Otherwise, it will be 200 N as long as they are in flight.</p>
<p>I don’t think so promemorex. If the pigeons are flying, they are not in contact with the cage, and therefore aren’t applying any force downwards. The pigeons are a separate entity that does not affect the scale.</p>
<p>So it should be C, 200 N right?</p>
<p>i agree and i think it should be 200 N</p>
<p>Yeah, I think it should be 200N.</p>
<p>But the pigeons fly by exerting a downward force on the air, which can exert a force on the cage.</p>
<p>Does anyone have a list of scientists we should know for the test?</p>
<p>We have to know scientists? O<em>O
As in when was Albert Einstein born?-</em>-</p>
<p>@ZeDschermen</p>
<p>no … we don’t , but we need to know what they did, like who made Charles’s Law? : Charles
Who made Kepler’s laws? Kepler … etc
of course, it won’t be that easy on the test.</p>
<p>do you get panelized for guessing and what is the pacing like?</p>
<p>hey, i also got a prob w/ sparknotes here too…totally failed at the second time. did much better the first time…
and barron’s seem much easier than sparknotes, but totally ask questios that prob shouldn’t appear on the test.
oh, do we have to know some science history? like, matching laws/principles to scientists who discovered those.</p>
<p>The pigeons answer was: D (220 N). The scale reading won’t change. The air exerts an upward force on a bird, which for each bird averages to its weight. Newton #3 says that the bird pushes down on the air by the same amount, which in turn pushes down on the bottom of the coop by the same force.</p>
<p>For fun, see:</p>
<p><a href=“MythBusters (2007 season) - Wikipedia”>MythBusters (2007 season) - Wikipedia;
<p>Question: how accurate/helpful is the Barron’s book?
I’m just trying to gauge if the material and level of difficultly is relevant/accurate?</p>
<p>Hmm, what are other people scoring on the Barrons Physics?</p>
<p>I just took a test…did horribly… i got something like 760 ugh…</p>
<p>When do we get our scores back? (for the June exam) has collegeboard posted the date yet?</p>
<p>I believe it is 6/26 for scores via tcp/ip. Ignoring all other questions, and posting my own:</p>
<p>The period of a pendulum of length L is T = 2<em>pi</em>sqrt(L/g). For a pendulum on the earth’s surface, T=1 sec. The pendulum is now moved out into space, at an elevation of 2 earth radii. The period of the pendulum is now (remember, no calculators):</p>
<p>A) 4 sec
B) 3 sec
C) 2 sec
D) 1 sec
E) 1/2 sec</p>
<p>The acceleration due to gravity (g) is inversely proportional to the square of the radius. So, doubling the radius would give 1/4 g as the new acceleration. </p>
<p>Putting this into the equation, we have T<em>new = sqrt(1/(1/4)) T</em>initial = 2 T_initial. So, the answer is (C).</p>
<p>Close, but no. Don’t forget to read the question carefully.</p>
<p>The radius is not double, but tripled. “elevation of 2 earth radii” means 2 times the radius MORE right?</p>
<p>B)</p>