<p>Guys, what are you doing to study these last few days? I had been studying for US History until Friday and now I only have a few days left before this Physics exam and I am kind of screwed… What do you guys suggest I should do to cram/prepare? … :(</p>
<p>I’m in the same boat.
My physics teacher finished the very last few chapters the Friday before AP testing started, and I’ve barely been able to study cause I had 3 AP tests this week…
Still got 2 more to go, but Physics is the most important one for me.</p>
<p>GAH.
I’m looking over free response and multiple choice right now.
The MC is so fricken difficult omg x.x</p>
<p>Does anyone have any good review materials? Not a book but something online. Barrons kinda sucks and I’m freaking out now that I realize how hard this test might actually be.</p>
<p>I’ve been watching Khan Academy videos all day Much more interesting than reading a review book. I think the best way to review at this point is to take practice tests, grade them and then go back and review the concepts you’re unfamiliar with.</p>
<p>khan academy has really been useful for me too
if u take the 2009 mc test it will give you a breakdown of which questions were related to which topic, so it’ll be easy to figure out what you need help on.</p>
<p>Also, inside a charged conducting sphere, what are the values of the electric field, potential energy, and electric potential (in general)? How about on the surface of the sphere, and away from the sphere? Thanks in advance. The Princeton Review doesn’t explain it, even though I’ve seen conducting sphere problems on several FR and MC.</p>
<p>When ur calculating electric fields outside the sphere, you take the sphere point at the center, not the outside points.(because there are numberous charges on the surface of the sphere, and they all equally have the electric field on the point outside the sphere, we calculate with the point inside the center of the sphere (its hard to explain just in words… But i tried my best)</p>
<p>Since electric charge is spread uniformily throughout the sphere, we can say the whole sphere is charged. Using E= KQ/R^2, R is the distance from the outside of the sphere to the point of interest. </p>
<p>Inside a conducting sphere, the elctric field is zero at any point in the sphere. However, the electric potential is constant at any point in the sphere NOT ZERO. </p>
<p>Remeber V= KQ/R. Also, you must note that electric potential, V, is a scalar quantity. So to find the net potential you simply add potentials together. DO NOT TAKE THE ABSOLUTE VALUES OF Q for electric potential. The charge Q is only absolute valued for force and electric field equations. </p>
<p>If you have any other questions feel free to ask.</p>
<p>It is very important to note the differences between scalars and vectors because the AP exam loves to test those. Electric potential and potential energy are based on scalars. The electric field is based on vectors.</p>
<p>Simply put: If they tell you to find the direction of the electric field, find the direction on a positive test charge. To find magnitude, take the vector sum of kq/r^2.</p>
<p>To find potential, take V = k(q1/r1 + q2/r2 + … + qn/rn)
Then if they want the potential energy, use the formula U=qV, and multiply the potential by the charge.</p>
<p>Oh, and use these for point charges. If they have the parallel plates, use E= v/d.</p>
<p>And finally, they like to have that mass spectrometer, which produces centripetal motion.
qvB -> mv^2/r </p>
Much more interesting than reading a review book. I think the best way to review at this point is to take practice tests, grade them and then go back and review the concepts you’re unfamiliar with.</p>![http://i.imgur.com/O7ypQ.png[/url]](http://i.imgur.com/O7ypQ.png%5B/url%5D){kind=link}
