<p>yeah i got B and C on the first two q of the test, and I think I got D on the third q... but im prob wrong</p>
<p>how about the one where it asks in which of three cases momentum was conserved? I said I and II or something because the third choice was a freely swinging pendulum, and since mv = 0 at the obect's highest point and mv > 0 at its lowest point, momentum was not conserved there</p>
<p>Anyone remember the question that asked about what explained the difference between light and sound with respect to...something I don't remember, or the one about the metal rod (one of the choices was that it could be easily magnetized)?</p>
<p>^^Nope I'm pretty sure momentum is conserved in all cases. Does anyone remember getting the element copper as part of their answer for one question?</p>
<p>copper and glass? i think that's what you're referring to, and that is what I got.
and i think momentum is consered in all cases...</p>
<p>hmm... for some reason I think I put all cases also, but tripNip brings up a good point. However, conservation is usually used with respect to some sort of collision. In a pendulum, momentum is not constant, but in colliding pendulums, momemtum would be conserved.</p>
<p>I think..</p>
<p>what was the answer to the one that ask which car travel the longest distance. I thought it was B b/c it had the greatest area under it. Is that wrong?
what was the answer to efficeny problem ... I think I made a stupid mistake</p>
<p>and for the rod was it magnetized</p>
<p>Someone please answer...</p>
<p>i thought it was B also</p>
<p>efficiency was .6</p>
<p>and rod WAS NOT magnetized if i remember correctly</p>
<p>Clarification on the momentum question (explanation), eV question and the KE vs. time graph questions please.</p>
<p>but a permenant magnt can not have south and south poles</p>
<p>I agree with Kian but there's a good chance I'm wrong. Why? Because collegeboard hates me.</p>
<p>It was not magnetized because then if a magnet came close to it, the rod could be POLARIZED and would attract either way..which i think what it said in the problem</p>
<p>was the ans to one of them N and S poles</p>
<p>The question stated that both end of the rod is attracted to the permanent magnet, so i put the rod has two south poles.</p>
<p>ok first of all...ALL magnets have a north and south pole so the rod couldnt have 2 sourth poles, and secondly, if it had a north and south, it would repel in one of the sides</p>
<p>if i was uncharged, like say a soda can, then it would be attracted by a magnet no matter what side/pole....you can check it yourself or search for magnetic polarization</p>
<p>magnets question answer was magnetisable material - as this fulfills either the non-magnetised or magnet (which is magnetised material) argument</p>
<p>i'm pretty sure in the pulley question</p>
<pre><code> |
| <----this string therefore 2W
O
| |
</code></pre>
<p>W W</p>
<p>query about the question with liquid at boiling point in an open container?</p>
<p>Well, i don't know if this works. Can a magnet has a north pole in the middle and 2 south poles at ends?</p>
<p>No to youknowme. Ans to james.gin if it asked for the tension on the string. It was W for sure. Just look it up. Its like one end of the string was attached to the wall and W was hanging from the other end of the pulley. Except on that problem, the other side was also a pulley with W hanging off of it. so it was W because of action-reaction forces.</p>
<p>Ive been thinking about the pulley question and I think the only way it could have been worded to cause so much confusion would me "what is the tension in the rope over the pulley" </p>
<p>This could be interpreted as the rope that is on the pulley or the rope the pulley is hanging from
(hoping that it is the rope on the pulley)</p>
<p>Im also looking for an answer to the one with boiling water and open container</p>