The AP Physics B Study Thread

<p>Well since there're 70 MC questions and 90 points on FRQ, so the maximum is around 160?</p>

<p>Aren't they weighted the same, so I'd imagine that you would have to multiply a constant to both MC and FR to make them equate.</p>

<p>If that's true, then the total points would have to be at least 180, unless FRQ is multiplied by a constant factor < 1</p>

<p>Is this statement true:
(potential energy) = -W = -qEd = qV = (kinetic energy) = .5mv^2</p>

<p>And what are the minus signs there for?</p>

<p>mgh=1/2mv^2</p>

<p>Of 2 points in a uniform electric field, how do we determine which point is at higher potential?</p>

<p>5) "Calculate how much work is required to move a test charge from one location to another in the field of fixed point charges."</p>

<p>6) "Calculate the electrostatic potential energy of a system of two or more point charges, and calculate how much work is reuqired to estblish the charge system."</p>

<p>W=FD</p>

<p>F=qE</p>

<p>so W=qeD ?</p>

<p>U=-(qeD)</p>

<p>
[quote]
Of 2 points in a uniform electric field, how do we determine which point is at higher potential?

[/quote]
</p>

<p>We can just use the formula right? V = kq/r. Besides, the point closer to the positive charge should have the higher potential.</p>

<p>
[quote]
5) "Calculate how much work is required to move a test charge from one location to another in the field of fixed point charges."

[/quote]
</p>

<p>I think this one can also be answered by finding the difference in potential energy, delta U. U = kqq/r, I believe, so the work would be U,final - U,initial.</p>

<p>


</p>

<p>Here's the full thing:
"Calculate the potential difference between two points in a uniform electric field, and state which point is at the higher potential."</p>

<p>I'm thinking about using U = (kQ1Q2)/r, but I don't know how to manipulate that to determine which point is at higher potential.</p>

<p>According to <a href="http://apcentral.collegeboard.com/repository/ap05_2006_exam_format_46933.pdf%5B/url%5D"&gt;http://apcentral.collegeboard.com/repository/ap05_2006_exam_format_46933.pdf&lt;/a&gt;&lt;/p>

<p>section I and section II are weighted equally... so we can safely assume something like</p>

<p>Section I, total 70 points * 1.2857
Section II, total 90 points * 1</p>

<p>Added up to 180 or something</p>

<p>and 75% is a 5</p>

<p>so you need to score 135+</p>

<p>that is, until new information confirms/disproves this</p>

<p>ok time to sleep</p>

<p>wow Im looking </p>

<p>BLEGH</p>

<p>"Determine the ratio of voltages for capacitors connected in series."</p>

<p>for resistors, the resistance adds up in series</p>

<p>capacitors are the exact opposite, their resistance adds up reciprocally in series
1/C1 + 1/C2 + .... 1/Cn = 1/CT</p>

<p>in series, current stays same, voltage is different.</p>

<p>so the voltages would be different by a factor of 1/C from the original?
please post the entire question (if any numbers are given) cause i'm confused.....</p>

<p>Well it isn't exactly a question, it's just something we should know. (all we have to know is the process in doing it)</p>

<p>Also how do we "calculate the number of photons per second emitted by a monochromatic source of specific wavelength and power" ? (notice that I'm putting it in quotes to show that these are direcly stated by CB of the things we should know)</p>

<p>E = hf, which is the energy of each photon</p>

<p>P = W / t. So when t = 1, then P is just the total energy output. Divide the energy of each individual photon into total output gives the number of photons emitted.</p>

<p>P / E = n</p>

<p>About studying for the B exam:
I'm using the Kaplan 2006-07 AP Physics B and C review book. Is this a good choice of literature? Or should I switch to something like Princeton Review? The review questions in Kaplan seem too easy compared to some questions I glimpsed in the PReview. Does Kaplan provide a good simulation of the test?</p>

<p>Also, I'm worried because my AP Physics teacher has barely discussed optics and has never taught the class anything about magnetism or atomic physics. I really want a 5, but with so little time to study at least 25% of the test... Does anyone have any strategies for making up for lost time in these last few weeks before the test?</p>

<p>I really appreciate your advice!</p>

<p>Well I haven't tried Kaplan, so use it if you feel comfortable. Also, you should read your textbook on things that you can manage to read, because it is far more detailed.</p>

<p>If you haven't touched optics, EM, and nuclear stuff... then I would have to say that you are pretty behind. They cover, together, around 50-60 % of the entire test, if I am correct. You need to cram pretty hard... as that's all we've done this semster.</p>

<p>According to the official 2004 released exam, the breakdown for the AP Physics B Exam is:
118-180
91- 114
63-90
49-62
0-48</p>