<p>can someone compile answers and questions? That would be awesome :-)</p>
<p>anyone remember the question given the charge of a particle, and the electric field… we were suppose to solve for something (all values were 10^-(xx) where xx is a double digit)…</p>
<p>I thought it related to [V=kq/d</a> or W=qEd [Archive] - Physics Forums](<a href=“V=kq/d or W=qEd”>V=kq/d or W=qEd)
but I don’t remember…</p>
<p>Also, GreeIsGood, because they are in phase, they increase on the right of P (one resulting wave)… principles of superposition</p>
<p>I thought the wave has a maximum at P and therefore it will be less on either side.</p>
<p>Can someone explain to me how the airplane one has a net force of 0? I interpreted the question as the airplane moving at a constant height above earth. is that right? if so, doesn’t the velocity constantly change, not the magnitude but the direction, meaning that there’s a force of some kind?</p>
<p>whether it has a maximum or minimum, if they are in phase, the amplitudes are added to each other.</p>
<p>i don’t remember the question 100%… what did it question that increased/decreased around P?</p>
<p>there was a line l, and then a point P on the line. </p>
<p>I worked it out and there was constructive interference at P which means that the amplitudes are decreasing to the left and right of P.</p>
<p>Friendly Reminder: Don’t discuss the test questions. I don’t know how much the mods/collegeboard follow these sorts of things, but you would not want to take the chance. :/</p>
<p>^ What? Aren’t we allowed to?
I thought only for AP you can’t discuss the multiple choice.</p>
<p>No the amplitude is increasing to the left of p since the waves are in phase and build up to complete constructive. On the other aide of p, they decrease because the waves leave each other (as the incident angles are different) and the superpositioned wave’s amplitude decreases.</p>
<p>Anyone remember any other questions? I’m dying to find out. Sadly, I have awful memory and I forget almost everything on the test.</p>
<p>Wait what, are we seriously not allowed to discuss the specific questions?
I just read the sticky now that said we can’t.
How come everyone did then?
I must admit that I thought it was okay because everyone else did (compared to in the AP threads when no one did because they knew they weren’t allowed).</p>
<p>The waves are at a maximum at P, would we all agree?</p>
<p>That means that means that everywhere around P, the amplitude is less.</p>
<p>What review books did you guys use? I’m taking it in June. And was it effective?</p>
<p>@cortana, I started with Kaplan, then moved on to the SAT blue blook (just to realize how much of a JOKE Kaplan was)… then I started doing Barron’s and interchanged between Barron’s, Princton Review, and the Princeton Review SAT II Physics Workbook…</p>
<p>How did PR do for this test? Did it prepare you well?</p>
<p>abrayo- no not really, but college confidential has gotten away with it for the past 10 years or so. That’s because we’re discussing “hypothetical questions from a practice test that we all happened to take in the morning of May 7” and I don’t really think they care as long as we discuss the questions after Hawaii finishes taking the exam. </p>
<p>CeilingFanFly- I suppose if you consider that the airplane is traveling on a curved earth, then there would be a very small centripetal force if that is what you are trying to say, but I don’t think collegeboard would consider that a net force since it mv^2/R would be more or less zero.</p>
<p>For the wavefront at P, I put that “more info was needed” I forgot why though… possibly because you were’t given the lengths of the two strings or something, though I don’t remember.</p>
<p>Also, for lightbulb question (discussed very long ago) the Req of the circuit increases because the lightbulb unscrewed was parallel with another (1/R = 1/R1 +1/R2 for parallel circuits), so current decreases</p>
<p>For the 1/20 wave question, I thought that the wave only moved half a wavelength so frequency would be 10 instead of 20 (if it moved a full wavelength, you wouldn’t be able to tell the difference between the first and the second picture since one period would have elapsed)</p>
<p>crap i think you’re right about the wavelength problem…</p>
<p>God i hate collegeboard tricks…</p>
<p>I do think that collegeboard does not want to discuss specific questions (I remember the proctor saying “under any circumstances…” before reading off a list of how not to reproduce or discuss the questions. But since no one has heard anything from the mods, maybe they don’t really mind? I’m just a natural paranoid person, and you may want to edit your posts after a while.</p>
<p>I used the Barron’s book to prepare myself for the test, but I hated the book when I looked at the practice tests. Maybe I was never in the test mood when I was reviewing, but I kept thinking how a lot of the problems had nothing to do with actual physics.</p>
<p>whale whale: </p>
<p>The total resistance decreased, you removed the one that was in series with it. Thus the total internal resistance decreased –> current increases.
Thus makes since with the other question which ones D> B > A=C or something.</p>
<p>Also for the 1/20 thing it was 40 m/s. It moved 1/2 of a period, (logical reasoning was used to show it could not have moved 1 wavelength or any other factor of 1, because then the graph would have appeared the exact same as the 1st). Thus 2/ (1/20) = 40 m/s.</p>
<p>The question about the standing wave of 20 Hz, and the length of .4m was 16 m/s. Velocity = f * wavelength, could be easily determined by f = v / 2L. </p>
<p>Other tricky questions included: the grouding RB question. I forgot the question but because the neutral conductor was grounded, there is an unlimited supply of electrions; I think the RB became - (normally it would remain electrically neutral if it were not grounded)</p>
<p>Anything else?</p>