<p>there are only two people in my ap physics class! and the exam is going to be held in a large auditorium, with the proctor, my friend and i. i can’t wait.</p>
<p>i’m taking physics C mech and i was wondering, why is PR better than Barron… because that’s what i heard in another thread.</p>
<p>Lol I was wondering where this thread died to. Keep it alive!</p>
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[QUOTE=Derivate]
5 days left… Finished BC today; was not that bad. How does Physics E+M difficulty compare to BC?
[/quote]
</p>
<p>Its harder than BC, I’d say. Then again, I did AB this year. -.-
I probably could’ve handled BC too, just didn’t wanna overload on the math (Stat + AB was enough).
Well for Calc, you know what you’re doing for each problem and that will get you somewhere, somehow. Physics, however, you need to think hard before writing stuff down.</p>
<p>For E&M, basically every single problem requires integrals (except well…circuits; you need differential equations for those). So if your Calc foundation is strong, you’ll find it fairly manageable (I’d imagine so for you, since you’ve done BC).</p>
<p>Mechanics is more physics-based than calculus. There’s just about one or two integral formulas to remember and the whole position-velocity-acceleration chain system (differentials and integrals of those).
How’s your self-studying coming along, btw?
Tried any practice tests yet?</p>
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[QUOTE=whheex]
there are only two people in my ap physics class! and the exam is going to be held in a large auditorium, with the proctor, my friend and i. i can’t wait.</p>
<p>i’m taking physics C mech and i was wondering, why is PR better than Barron… because that’s what i heard in another thread.
[/quote]
</p>
<p>Lol. Two? For real?
We’ve got about 50 people doing both Mechanics AND E&M.</p>
<p>And oh yeah, I’d recommend PR over Barron because of their explanation system. If you’re confused about a problem, you don’t wanna know what the answer is, you wanna know HOW to do such a problem. Barron’s, imo, just assumes that you knew it and just didn’t know how to apply it so their explanation is kinda vague (this is strictly my opinion).
Its good for practice given you’re already an expert in Physics (which I’m not).
PR is helpful for everyone else, and self-studiers.</p>
<p>I am freaking out about this exam. I got 4 on the first mock and 3 on the 2nd mock. I did terribly on both FR and MC.</p>
<p>How do you guys review for the exam ?? I don’t know what to review.</p>
<p>I am madly reviewing the E+M. My Calculus foundation is quite solid, and I am starting to get a feel for exactly when to integrate to find electric field etc.</p>
<p>I will be the only one taking Physics C at my school, but I think they are going to lump me in with a bunch of Physics B people during the exam, but I’ll get a notice for 45 minutes interval.</p>
<p>Can someone give me a dirty rundown of electric potential? Like inside conductors, insulators, and such.</p>
<p>
[QUOTE=nns91]
I am freaking out about this exam. I got 4 on the first mock and 3 on the 2nd mock. I did terribly on both FR and MC.</p>
<p>How do you guys review for the exam ?? I don’t know what to review
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</p>
<p>Don’t worry man, I got two 4’s on both practice tests that we did in class (Mech and E&M). Then again, they were just lower than what is considered a mid-4.
I’m happy with a 4 on both, but a 5’s would show epicness to my colleges, lol.</p>
<p>To review, run down on important concepts from EACH chapter and try a practice FRQ to see how much you can answer. If you get 10+ points out of 15, you’re in great shape.</p>
<p>Ch33psh33p, thats the work integral for E&M.
V(at whatever point) - V(at another point) = Integral (E . dx)
Remember this is a path integral.
There is some review guide on the web somewhere that I saw a while back, I’ll post it if I can find it again.</p>
<p>So the cutoff for a 5 on Mech and E&M is around a 50ish?</p>
<p>Electric potential is U/q or integral of E (dot) dx</p>
<p>Electric field inside a conductor is zero so V is constant and is the same value as that on the surface of the conductor.</p>
<p>For insulators you just do ratio of the radii^3 times the volume charge density to find the total enclosed charge and use kQ/r to find the potential.</p>
<p>When a circuit question says “after a long period of time has passed”, what exactly does that imply?</p>
<p>The capacitor is fully charged, but is that it? Does it also imply that the voltage source is depleted, as in, it equals 0? Since that does happen with any “real” voltage source after an “infinite” period of time.</p>
<p>After a long period of time has passed means its FULLY CHARGED.
Or Q=CV
No voltage isnt depleted.</p>
<p>Its asking you to evaluate the circuit at t = infinity.
This is when the difference in voltage across the battery equals the difference in voltage across the capacitor (equilibrium has been reached at t = infinity).
Write the kirchoff, and then there is NO current flowing ** through the capacitor **because the capacitor is fully charged, but there IS a voltage difference across its plates(V = Q/C).</p>
<p><em>bumpeth</em></p>
<p>A charged particle moving in the presence of both an electric and a magnetic field moves in a closed path (a path that begins and ends at the same point). If the energy of the particle at the end of the path is 2.0 J greater than its energy when it began the path, which of the following statements is correct?</p>
<p>A) The magnetic field performed 2.0 J of work on the particle.
B) The magnetic field performed -2.0 J of work on the particle.
C) The electric field is conservative.
D) The electric field is due to static charges.
E) none of the above</p>
<p>I’m going to take a wild guess and say it’s d.
Magnetic field can’t do work, it’s perpendicular.
C is wrong I think because electric FORCE is conservative, can “field” be conservative?
D? E?</p>
<p>How hard are the Princeton review tests compared to the actual thing? Because they seem pretty hard, but I thought they were supposed to be on the easier side.</p>
<p>@jhang: Lol I would’ve guessed D too, just can’t explain why. And I don’t know the answer, thats why I’m asking!</p>
<p>PR practice tests are equally as difficult as the actual thing, Barron’s is HARDER (they even say that themselves).</p>
<p>I’d guess A. I’m pretty sure that electric fields are conservative and magnetic fields aren’t conservative, so that answer makes a lot of sense at least to me.</p>
<p>Can’t be C or D – they are equivalent: electric fields due to static charges are conservative – if you return to your starting point, work = 0. So this must be the result of an electromagnetically induced electric field (caused by changing magnetic field).</p>
<p>Answer should be E… A & B are not because mag fields do no work. Conservative electric fields don’t allow a change in direction without work being done on the particle (which the mag fields can’t do). Static charges aren’t a factor in electric fields.</p>
<p>Yeah, magnetic field does no work.
But a CHANGE in magnetic field produces a CHANGE in electric field, i.e., work IS done on the particle.
I think I’d guess A too…don’t know how much thats correct.</p>
<p>And another question:
When you have a wire loop (or anything) moving in a constant magnetic field (into/out of the page), is the magnetic force always opposite to the direction of motion or would you use the right-hand-rule to find the direction?</p>
<p>Self Studying both parts of C, some of mechanics was covered in class, none of E&M was covered in class, but I think I’ll probably get around a 4 on both, thats what I got on my first practice test forem, haha, the funny thing is on my E&M practice I only got 16/35 MC…but thanks to a ridiculous curve, and getting like 66 percent of the FR points…its somehow a 4?</p>
<p>And for that one I would say right hand rule, if you wanna find current of the induced loop as well, you might wanna use both right hand rules</p>
<p>but don’t trust me, I kinda suck at E&M</p>
<p>“Static charges aren’t a factor in electric fields”</p>
<p>This is not true. Static charges DO cause electric fields, but those fields are conservative.</p>
<p>And since magnetic fields don’t do work on isolated charges, that rules out A and B too. So it is E.</p>