***Official Physics B thread 2012-2013***

<p>Any good resources online you guys have found?</p>

<p>It seems as if my little thread has taken off in my absence.</p>

<p>I’m on mirrors/refraction. We just finished sound.</p>

<p>glhf on the exam</p>

<p>i finished everything. crammin for sat II.
DAMN YOU CHAOS THEORY!!!</p>

<p>Well, we finished learning new concepts in my school. Guess it is just up to reviewing now.</p>

<p>@Texas, I’m jealous, we’re learning about electric currents…</p>

<p>We’re done and I’m starting to think I’m not going to get a 5. <em>shrugs</em> It’s not for Physics I credit so I don’t feel so bad XD</p>

<p>Yeah, we finished just last week. Now we’re going backwards through the course reviewing all the material… Yay for review packets and physics videos every night…</p>

<p>My class hasnt even gotten to magnetism or atomic and nuclear physics but yolo I took the mock exam and got a 5 before i learned electricity so fingers crossed</p>

<p>^wat… some people have all the luck</p>

<p>just took the 2012 exam as a mock with different FRQ. GOT A FIVE!!! So shocked. 1/4 people in like 60 people. 50/70 on mc and 61/80 on frq. 135/180. The curve for this exam was extremely high though. 129/180. I believe its the same exam all ap physics teachers got as a mock to give students.
Taking the subject test tomorow. So scared…</p>

<p>Wow, there is a meager amount of resources so I thought I’d lend out a hand to all my AP Physic B’ers
AP Physics B&C McGraw Hill: [AP</a> Physics B-C 2008-2009.pdf - Speedy Share - upload your files here](<a href=“http://speedy.sh/vNRey/AP-Physics-B-C-2008-2009.pdf]AP”>Loading...)
Online sites:

  1. [AP</a> Physics B Practice Exam | Education.com](<a href=“http://www.education.com/study-help/article/physics-practice-exammultiple-choice-questions/]AP”>Education.com | #1 Educational Site for Pre-K to 8th Grade)
  2. [Torrey</a> Pines Physics](<a href=“http://teachers.sduhsd.net/tpscience/physics/physicsB.html]Torrey”>http://teachers.sduhsd.net/tpscience/physics/physicsB.html)</p>

<p>Hope this helps!</p>

<p>alright…lets start a discussion</p>

<p>Ugh…MC were a joke.
The FRQ were also a joke, except the one with the wire X and Wire Y.
How were you supposed to find the current in wire Y?!</p>

<p>The masses one was okay, except what did you guys get for the Mass of the block and why the range decreases with increasing mass? </p>

<p>Bouyancy, spring, refraction, and thermo questions were cake.
Ionization was iffy, but do-able.
Hopefully a 5!!! :-]</p>

<p>For a pulley system, if the setup is frictionless, the rightward force on a cart being pulled towards an edge is equal to the gravitational force of the block pulling down. However, when calculating the acceleration from that rightward force, it should be noted that the mass of the entire system should be used, like this:</p>

<p>(mass of falling block)(9.81m/s^2)=(mass of falling block+total mass of cart and contents)(acceleration of cart)</p>

<p>If the mass of the falling block and the mass of the cart remain constant, as the mass of the contents increases the acceleration will decrease, and therefore the content (projectile) will travel less far.</p>

<p>Sounds about right.</p>

<p>What did you get for the current of the wire?
I was really upset at that question :[</p>

<p>bil=mg you have mass length so bi=mg/l. Just solve.
how do you ionization?</p>

<p>the mc with energy equivalent got me. others were cake.</p>

<p>Ionization energy is the energy required to remove an electron from ground state to infinity.</p>

<p>So you just subtract the two energy’s. I believe it was 14 eV</p>

<p>For the wire question, were the electic potentials equal at both ends?</p>

<p>Also, what direction was the current going in for wire Y?</p>

<p>What happened to the current of wire Y when the wire was moved above wire X? </p>

<p>Also, ESWARA20: you said bi=mg/l, I agree with that, but what did you use for b?</p>

<p>12ev i think… yeah the wire current is BIL=mg
BI=(m/L)g, solve from there.
For the carnot heat engine, this might sound stupid but does it go from low temperature to high temperature? I remember in class talking about heat engines moving heat from a cold reservoir to hot reservoir or something…</p>