AP Physics C: Mechanics Form B Post-Discussion

<p>There was no forum made for the form b of the AP Physics C: Mechanics so go ahead and post any questions or concerns here. Here is my question:
For the AP Physics C: Mechanics form B (which is the late testing version), on question 2, I accidentally made the normal force = mgsin(theta) instead of mgcos(theta), which made my horizontal forces mgcos(theta). I consistently did this throughout the question. Will I receive no credit for deriving an expression of the net force in the horizontal direction because I put the wrong trig function? Please someone answer me, I'm dying to know</p>

<p>My bad, form b is not late testing, but can someone still answer my question?</p>

<p>Wow dude, thanks for telling me that, and by the way I did take the EM test and when I hit the middle of the frq, I rose my hand and cancelled my score. It definitely was that difficult. Funny thing is, as soon as I cancelled my score, the only other person taking the EM test rose his hand and cancelled his score too. It was just ridiculously hard!!</p>

<p>I did the EM test yesterday. I think I got 80% on MC. FRQ #1 destroyed me, but at the end, I came back to it, and I hope I got 50% of the points. FRQs 2 was okay once I figured out the 1st 2 parts(though for the power part, I forgot to square voltage and thus got R=0; Oh, well). Hope for 70-80% points on that. #3 was really easy; just a bunch of derivatives and substitutions. Hopefully, 80-90% of points on that.</p>

<p>For FRQ 1, the slab is like a parallel plate if you’re outside it, right?</p>

<p>I used the parallel plate formula, which is (charge density)/2epsilon. Not sure if I’m allowed to cite that(I didn’t use a gaussian surface for that, but it would be a rectangular box; since the field is only in the x direction, the flux is only thru 2 of the sides. </p>

<p>I think we’ll lose onlt 1 point: they probably give 1 point for P=V^2/R, 1 point for deriving power in terms of R and r, and 1 pt for the answer. However, assuming that R=0 follows from the incorrect expression for power, we should still get the point for the answer since it follows from our expression.</p>

<p>You may lose a point by losing a factor of 2…</p>

<p>Don’t worry too much, a 62% is a 5</p>

<p>20/35=4/7=26 raw points out of 45.
30/45(on FRQ)=30 raw points out of 45
Add them up, and the result is 56.
According to this: <a href=“Supporting Students from Day One to Exam Day – AP Central | College Board”>Supporting Students from Day One to Exam Day – AP Central | College Board;
53 is a 5. So you’re a low 5 or high 4; I doubt it’ll be a 4, since this test seems harder than usual.</p>

<p>In conclusion, maybe you should reconsider cancelling your score.</p>

<p>I think you should not cancel your score.</p>

<p>I found it somewhat difficult, but mainly because there was so little time; after I calmed down and thought for a while, the problems weren’t that bad.</p>

<p>I advise none of you to cancel your scores. You can epically fail the AP Physics C exams and still get a 3.</p>

<p>rapevictim- that’s from general knowledge. The curve is sometimes as low as 30% for a 3.</p>