<p>^ holy crap. That’s intense man. You are looking at least 6 hours of testing.</p>
<p>
I didn’t know which college I was going to when I signed up…</p>
<p>A pair of identical negative charges (both with mass m) are attached separately, one to a vertical spring and the other to a pendulum (assume they are far enough apart to neglect their mutual electrical repulsion). The periods of oscillation of both are measured to be 1 second.</p>
<p>Both are now placed between the horizontal plates of a very large capacitor whose positive charge is on the upper plate. Which of the following is true?</p>
<p>A) The periods of both are still 1 second.
B) The period of the pendulum is now greater than 1 second, the spring period is now less than 1 second.
C) The period of the pendulum is now greater than 1 second, the spring period remains 1 second.
D) The period of the pendulum remains 1 second, the spring period is now greater than 1 second.
E) The period of the pendulum is now less than 1 second, the spring period remains 1 second.</p>
<p>^ is it D?</p>
<p>I seriously hate springs and pendulums. I’d probably skip this one if it was to show up on a MC, but if I had to guess, I’d guess D.
Is it right? lol.</p>
<p>no can’t be D, the electric force opposes the gravitational force so the net force acting on the pendulum (and thus the net acceleration) isn’t the same</p>
<p>Spring period remains 1 second since all the electric force does is shift the equilibrium position.</p>
<p>Hmmm, since the net force acting on the pendulum decreases, I would think the period increases. C?</p>
<p>One of the many things I don’t get is when to use L = I(omega) and when to use L = rmv… I sometimes use these two interchangeably and then screw myself over.</p>
<p>do you think its possible to get a 5 on the mech part with just physics b knowledge? im just curious, since im self studying mech this year an am enrolled in physics b at school.</p>
<p>^ What math are you in?
If you don’t have any calculus knowledge, its really hard to get a 5.
Lots of mechanics (especially kinematics) asks you to write differential equations for some variables.
You need to be overly good at physics to get a 5 with B-knowledge (I mean you know what you’re doing for every single problem and are ready to ace anything thrown at you).</p>
<p>im in ap calc bc now
i’ve been using princeton review and barron’s for the extra physics c stuff…hopefully ok? :P</p>
<p>Lol so you HAVE been studying, why’d you say you had only B-knowledge?</p>
<p>Yes thats great, you’ll do fine.
If you’re actually feeling good, you can get a 5.
(I took the course and yet expecting a 4 lol…atleast thats what I got on both the practice tests we did in class). Some stuff just confuses you beyond belief.</p>
<p>haha lets just say i have a lot of studying left to do…im taking it on the 22nd though (make up)</p>
<p>im self studying
using princeton review, no course in school
i find that 45 minutes for 35 MC is not enough time to get a decent score
right now, about like 50somefin percent…T.T</p>
<p>^ yep same.
I feel 45 mins is too little even for the FRQs…even though there’s three and you get 15 mins for each one. I’d like an entire hour. -_-</p>
<p>Yea, answering 35 MC in 45 mins is a bit too much, especially with the insane amount of concepts you need to know.</p>
<p>those of you taking bio and both parts of physics c know that you are allowed to take one exam late without penalty if youd like, right?</p>
<p>You use L = I * omega when an object is rotating about an axis that is NOT it’s center of mass. You only use L = mrv when your treating it like a point or its rotating about its c.m.</p>
<p>Physics C both Mech and E&M are toooooo easy. I’m studying for Chem, and a tiny bit of English Language…:)</p>
<p>hahahaha. I hate physics with the passion of a thousand suns. Our teacher is actually terrible. I think I’ll probably end up with a 4 though, maybe a 5 if i can really study this weekend. Good luck to all of us. I’m definitely going to need it.</p>
<p>Haha, yeah tomhuu I’m self studying it too. Our school only offers up to honors physics and since It seemed like a joke of a class, I figured why not take AP Physics C…both parts.</p>
<p>So mechanics we actually learned some of it in class, but definitely not as in depth as in C, but we haven’t done ANY E&M so far, so the last week I took the princeton book and basically knocked out a chapter a day of E&M going through each example problem and multiple choice at the end of the chapter. And now I actually feel pretty good about it, all I need is a 3 though…so I don’t think thatll be hard at all, but for pride I’m shooting for at least a 4 on each. The only things i’m weak on really are torque, rotational motion, inductors, electromagnetic induction, and alot of the integration on E&M I can never get the right formula down to integrate</p>
<p>Anyone know if buoyancy is on the Mechanics test?
I remember doing problems in class, don’t know if its part of the test.
You deal with it just like any other force…but it gets weird at times.
Any confirmation?</p>
<p>Practice for you guys:</p>
<p>The period of a pendulum of length L is T = 2<em>pi</em>sqrt(L/g). For a particular 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 (no calculators!):</p>
<p>A) 4 sec
B) 3 sec
C) 2 sec
D) 1 sec
E) 1/2 sec</p>