*** Official AP Physics B Discussion Thread 2013-2014 ***

<p>:/</p>

<p>MC was harder than MC 2009 <a href=“http://www.freebookez.com/ebook.php?u=aHR0cDovL215c2l0ZS5jaGVyb2tlZS5rMTIuZ2EudXMvcGVyc29uYWwvZG9uYV9iaWVuLWFpbWUvc2l0ZS9MaXN0cy9DbGFzcyUyMDElMjBIb21ld29yay9BdHRhY2htZW50cy8xNS9BUCUyMEIlMjAyMDA5JTIwTUMlMjAoMSkucGRmCkFQIEIgMjAwOSBNQyAoMSkucGRm”>Loading...;

<p>What did you guys get for the 2 consecutive current problems about the series circuit? They were in the 10-15 range for form O. I put E/3R for both because I assumed that current stayed the same. Is that right? </p>

<p>@OnMyGrind thats what i said. idk if its right or not</p>

<p>All I can say is that I’m glad this class and exam is over. Hoping for a high 4 or low 5.</p>

<p>I put E/3R for one and E/R for the other. I don’t remember what the question was though haha </p>

<p>I put 0 for one and E/3R for the other.</p>

<p>for the free response on the photoelectric effect, did you guys get remain the same for both the last two parts?</p>

<p>I said both remained the same because intensity does not affect energy and wavelength does not affect number of photons
What was the electric potential at that point? I got the components were 6 and 18, but i dint know what to do with them because they aren’t vectors…</p>

<p>I had the same problem crazy frog… But I really think I made dumb errors on a lot of it. I’m thinking a 4… </p>

<p>crazy frog i’m not sure which question you’re referring to but if you’re talking about the electricity free response i got 6 and 2 for the components i think (but that was asking about e field)
also, for the buoyancy question was the last part remain the same too?
i got so many remain the same’s its very worrying</p>

<p>6 and 2 here as well. But I kept forgetting the rules and how to make them go together as one thing, because they aren’t vectors… So Idk >_<
And I put too many too… I ended up going back last minute and changing some of them because it seemed wrong. I hope I didn’t screw myself with that. </p>

<p>Electric field is a vector, add them like compontents.</p>

<p>Electric potential is not vector, you plug in the values and add (make sure for electric potential you put the sign of charge as well).</p>

<p>I got 6 and 2 for electric field, and 6 and 18 for the electric potential (because it is over r, not r^2)</p>

<p>Hey guys, what did you get for the problem where it asked to find velocity and net force when you just let go of the pendulum bob (left position). I think everybody got velocity as tangentially down and to the right. But I see people saying they got acceleration as back to the center of the circle (in the direction of the tension), but I thought net force would be the sum of the gravity vector and the tension vector, therefore a little down and to the right.</p>

<p>@Pentakis‌ You may have misread. Yes clockwise means negative work, but that means negative work ON the gas, and the question asked for positive work done BY the gas which is equal to negative work ON the gas. :confused: sorry dude, but I’m pretty sure about this one too.</p>

<p>@SFHKBOI‌ is that a mc or fr question? i can’t remember</p>

<p>also for the buoyancy question was the last part remain the same too? anyoneeee haha</p>

<p>@vivalamelanie‌ i got the same. and i was talking about a mc question</p>

<p>I think I did OK on this test. I nailed the MC, with only a few questions I wasn’t sure about. I completely answered 5 of the frqs, but two I probably only got 2-3pts on (but I got the 15 pointers good). On frq 6 (form o) I wrote corny physics jokes and drew pictures on the last 3 parts. </p>

<p>@SFHKBOI Wouldn’t there be no velocity at the moment of release? By moment of release I assume that means when t=0 at which point there could not possibly be a velocity.</p>