<p>Uh, are the sample questions on Collegeboard’s website (like, in the course description) easier then? Because they were fine compared to Princeton Review.</p>
<p>4 hour study session at school today!</p>
<p>we actually dont get the formula sheet for mc?? my teachers d-ass</p>
<p>no, just for free response. Most of the MC, especially e and m, is more theoretical, though. Just remember the biggies for each subject area.</p>
<p>pckeller: Sorry, my mistake. I read the problem to say that static charges were not involved in why the particle was in the electric field. In that case, static charges wouldn’t be a factor in getting a particle back to it’s original position.</p>
<p>Lol I can’t believe you guys self-studied and are feeling so good about the tests.
Getting a 4 on both with a one semester course in Mech and another semester in E&M is kinda embarrassing. Yea, the curve is pretty lenient (very…lenient) so people naturally good at equation manipulation and physics in general will most likely get a 5.</p>
<p>I’m looking forward to 4-ing both.</p>
<p>Btw, the answer is E (asked the smartest kid in our class).
A and B are ruled out because magnetic fields do no work (they are perpendicular to the particle’s displacement). Magnetic field performs no work on the particle, so in order for the particle to move, the electric field must perform work on it. Since it performs a net work, the field is not conservative, and fields due to static charges ARE always conservative. Only choice left is E. PoE ftw.</p>
<p>Yea, does anyone know if the sample multiple choice questions from Collegeboard are accurate at all?</p>
<p>Yep, Collegeboard MC examples are pretty accurate. But don’t expect to see stuff like that on it because almost everyone looks at those. Study from the practice tests in prep books. I can guarantee you that Barron’s tests are HARDER than the actual thing…I totally failed the Mechanics I MC in their practice test. </p>
<p>Btw, is buoyancy on the test or not?!!
Oh, and :
Does the Parallel Axis Theorem work for any shape (even irregular), as long as you’re determining the moment of inertia along a parallel plane?</p>
<p>Um… quick question:</p>
<p>How do you know when to integrate from 0 to t (or some other variable) and when to just do just an indefinite integral?</p>
<p>I took the 1998 Mechanics Multiple choice and I got 1 wrong and skipped 2. So I guess I am really happy.</p>
<p>But there are FRQs, and E+M to worry about.</p>
<p>But, if you guys are right about the magnetic and electric fields doing no work, how does the particle end up at a higher energy state?</p>
<p>Magnetic fields don’t do work, I think its possible for an electric field to.</p>
<p>It’s a complicated issue:</p>
<ol>
<li><p>Magnetic fields cannot do work on isolated charges ever – the force they exert is always perpendicular to the motion.</p></li>
<li><p>Electric fields CAN do work. But in this case, there was the added fact that the object returned to its starting point…</p></li>
<li><p>Electric fields can be caused two ways: by static charges (this is the “regular” way) and also by increasing magnetic fields. One key difference between these two types of fields is that the static-charge-caused E fields are conservative, while the changing-mag-field caused E fields are not. Static-charge-caused field lines flow out of + charges and into -. But magnetically induced E fields form closed loops. You can take a point charge around one of those loops and it will gain energy as it returns to its starting point. That never happens with “regular” electric fields. </p></li>
</ol>
<p>Hope this helps…</p>
<p>@feuxfollets: Its the same thing. An indefinite integral of dt actually has the limits of 0 to t (thats why it ends up becoming t by FTC).</p>
<p>And wow Derivate, 1 wrong + 2 skipped out of 35 is insanely good. You can probably skip two FRQs and get the last one semi-correct and still get a 5. O_o
Did you manage that in 45 mins? If so, thats really impressive. Gj!</p>
<p>^ I didn’t time myself, but I think it was within 45 minutes. </p>
<p>Mechanics is basically Physics B with some easy applied calculus. I think I am fairly good at calculus. However, E+M conceptually is difficult (although the integrating isn’t too difficult)</p>
<p>I find it weird, because on calculus I finished the MC with like 10-15 to spare, however on physics C, the last practice test I took I only even finished 25/35, albeit I got enough right for a 3(gotta love the curve) but the 45 minute time limit seems incredibly harsh compared to the other ap math type tests I’ve taken. Calc, 45 questions in a total of more than an hour and a half, stat, 40 in an hour and a half, comp sci, 40 in hour and 15, physics…35 in 45 minutes?</p>
<p>^ YES! I know.
45 mins is way too less for 35 MC, as compared to that of Stat/Calc…
I seriously need 60-70 mins. I randomly guessed on the last 10 (on the practice tests) because I kept running out of time. Better to leave them blank, imo.</p>
<p>For Calc MC Part II, you get 50 mins for 17 questions…
For Physics MC, you get 45 mins for 35 questions (which is a ton more work than Calc).
Thats simply not right.</p>
<p>at first i thought that 45 mins wasn’t enough either since on my first practice test i failed and got a 23…
but then i realized that speed is hella as important on this mc so what i did is i memorized the equation sheet a LOT so i can think about it faster.</p>
<p>that probably worked since i got a 31 on the next practice i took.</p>
<p>btw derivate, the questions you missed, were they conceptual questions (like conditions, etc.) or numerical answer questions? i usually miss some conceptual questions (stupid, stupid)</p>
<p>Ya it was conceptual.</p>
<p>Given a function for potential energy. Lets say U(r) = br^(-3/2) + c where b and c are constants. which of the following is an expression for the force on the particle. I integrated instead of differentiating. How stupid of me.</p>
<p>Then there was one that gave the equation for the motion of a simple harmonic oscillator given by the second derivative d^2x/dt^s = -9x where x is displacement and t is time. How would I find the period of oscillation?</p>
<p>Wow just took a practice test…got a 23/35 :[
I’m really worried about the Free Response on both Mech and E/M. E/M is gonna be so tough…</p>