<p>how do you do # 26 of '93?</p>
<p>o as long as one side of the lens is converging then it will cuase the parallel rays of light to converge</p>
<p>any other obscure questions?</p>
<p>thanks for the other answers!</p>
<p>ok more obscure questions~</p>
<p>12 and 70 from '93</p>
<p>i dont get 12 why is the accleeration upwards and 70 its because the electric potentai l for the smaller speherre is greater since its smaller radius and formula for electric potential is kq/r</p>
<p>so it's potential that needs to be balanced, not the charge?</p>
<p>yea its potential </p>
<p>can u please explain no. 12 im so lost and do u have the ap princetoon book</p>
<p>I'm lost too! I guess it's centripetal acceleration? but then the question didnt say its a circle...</p>
<p>and yeah i do have PR, but then im only 1/3 way thru it......</p>
<p>lol do u cink ure ready for the test and can u explain #67 on 1993</p>
<p>Yea #12 is because it is centripetal acceleration. The curve implies this. This means that the velocity vector must be tangential to the curve, and the acceleration must point towards the center of the "circle."</p>
<p>Yea I was also wondering how to do #67 on 1993 =.
O yea, also #65-66 on 1998.</p>
<p>zero786-- that's so tricky! It's like.. oh wait so that means the centripetal acceleration > g?</p>
<p>67 is an algebraic manipulation one. you know emf=V=flux/time=BA/t and V=IR, so IR=BA/t</p>
<p>B/t (change in field) then = IR/A</p>
<p>A, the area, is a^2</p>
<p>IR/a^2</p>
<p>ah ditto that zero786... I'm wondering about 65-66 too</p>
<p>how about #67</p>
<p>43 from 1993</p>
<p>OK i got 65 on 1998... the resistance in a wire is given by</p>
<p>R = pL/A where p = density, L - length, and A = cross sectional area. Since the radius is doubled, the cicumference or length is doubled, which means the resistance is doubled. As for 66... 9% got it correct. I think it's one we can skip =P</p>
<p>43 is a graph of position versus time, so the slope shows velocity. The acceleration is max when the change in velocity is max, and this is when the slope changes the most. This happens at 1 and 3 seconds. However, it says maximum positive acceleration, so this is at 1s. The velocity is changing from negative to positive there.</p>
<p>o.O how did you get the percentages zero?</p>
<p>omg! I just noticed taht I've been reading the questions wrong..... I thought the circles were cross-sectional areas of concentric wires ><</p>
<p>hey guys what do u cink will be the frq tomorrow</p>
<p>My answers come with percentages of people who got it right =P</p>
<p>yeah 43 is like 2nd derivative, if you know calc</p>