<p>for the problem with the charges in the field was the answer current carrying wire, or the magnetic field where north was the top and south was the bottom</p>
<p>-_- ..</p>
<p>is it legal to talk about it now?</p>
<p>oh?!really? I thought everyone had finished few hours ago</p>
<p>I don't think the half life one was 5x10^-3...if you think about it logically, the shorter the half-life, the flatter the curve gets...so it will be very hard to put an exact date on it. I answered C (5000 years) after eliminating that one, but I'm really not sure...I'm gonna ask my physics teacher on Monday, but I'm about 80% sure that a half-life that short is not desirable.</p>
<p>And about the graph w/ X,Y,Z and all that on it, I was SO happy that the night before I had carefully read PR's section on Modern Physics. Last year (when I took it cold, w/o ever learning thermal physics or some modern physics and waves) I got a 660 and would have been completely stumped at that one. I'll be happy with a 730+ this time around...it wasn't too bad I didn't think, but maybe I was thinking back to the first time I took it, when 2 minutes into the test I realized I was totally unprepared and panicked.</p>
<p>Yeah, I used PR (the AP book, it's written by the same author) and Sparknotes (Though, for future reference, just buy the PR SAT 2). After going through those, a lot of the questions seemed much easier. But I was glad I went through them because the practice tests helped a bit.</p>
<p>can anyone tell me the logic behind the half life for the mummy problem?</p>
<p>I thought it was 5000 because they said that they wanted to be able to measure it the easiest. If the mummy if 5000 years old, i think it will be easiest to measure if you know that exactly one half life has happened, which is 5000 years.</p>
<p>My problem with 5000 years was if the mummy is about 5000 years old, will anything have decayed to give an accurate result (I went with 5 for a lack of better choices).</p>
<p>same here !</p>
<p>On the question on planet orbiting sun was acceleration and velocity pointed just like in circular motion? Or no, because it's an ellipse?</p>
<p>I put that the Ac was pointing toward teh sun, since its an ellipse</p>
<p>for the mummy I put the answer choice with the smallest number, since that would be more accurate.</p>
<p>For the one where you had to choose if the current was a pole sticking straight up through teh field (choice a, i think), or going from south to north, or north to south, what was the correct answer? I think I put a.</p>
<p>and what was teh question with WXYZ? I somehow don't remember that one</p>
<p>What was answer choice a for the pole question?</p>
<p>oh nevermind </p>
<p>the WXYZ question, I just looked at the graph. For the first one I think I put E, and I don't remember for the second one.</p>
<p>ok for the mummy problem it is most accurate to use a 5000 year half life isotope for a simple reason</p>
<p>after 5000 years pass, 50% of the isotope will still remain which is easily measurable.</p>
<p>if the half life was 5 x 10 ^ -3 then after .005 years, it would go down in half. itll be impossible to measure how much is left after 5000 years.</p>
<p>that was exactly my reasoning</p>
<p>What about the transformer and motor problems? I never learned about these and I'm curious about the answers.</p>
<p>exactly my reasoning on the mummy too. I skipped the transformer and motor ones. I the XYZ, I said the first was one that Z will never loose 4 electrons, something like that, an the Y one was 4eV</p>
<p>How you solved the one with the ball being thrown horizontally and the ball being dropped?We had to find the distance between them.</p>