Help with E&M???

Test Preparation AP Test Preparation
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<p>1) <a href="http://tinyimage.net/images/25790944428468568236.png%5B/url%5D"&gt;http://tinyimage.net/images/25790944428468568236.png&lt;/a>
I don't even... The answer is B.. What should I review??</p>

<p>2)<a href="http://tinyimage.net/images/81684598844478119651.png%5B/url%5D"&gt;http://tinyimage.net/images/81684598844478119651.png&lt;/a>
Why can't I use the formula V^2/R for this one?? answer C btw ( I did get it right, but just because I didn't see the answer choice I needed had I used V^2/R...)</p>

<p>3)<a href="http://tinyimage.net/images/14929814429358178541.png%5B/url%5D"&gt;http://tinyimage.net/images/14929814429358178541.png&lt;/a>
How do I approach questions like 52? The answer is E.... (I get 51 though)</p>

<p>4)<a href="http://tinyimage.net/images/89661487184785817963.png%5B/url%5D"&gt;http://tinyimage.net/images/89661487184785817963.png&lt;/a>
Umm... I don't remember learning this.. What is this an application of?</p>

<p>5)<a href="http://tinyimage.net/images/05849919813601766271.png%5B/url%5D"&gt;http://tinyimage.net/images/05849919813601766271.png&lt;/a>
57:B -> Why is R2 ignored? I put A originally...
58:A -> I thought there is no current after a significant amount of time b/c capacitor takes up all the charge? no?</p>

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<p>this looks like halliday resnick. I’d advise you to just do AP questions, cuz HR is disgustingly tricky.</p>

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<p>umm they are actual ap problems -.-</p>

4

<p>well i will try</p>

<ol>
<li><p>no idea</p></li>
<li><p>P=I^2R
R = pL/A
therefore
P = I^2(pL)/(1/2d)^2
so it is directly proportional to p and L.</p></li>
<li><p>well the potential relative to infinity is the energy required to bring a charge from infinity to r.</p></li>
</ol>

<p>so it would be W inf-r2 + Wr2-r
= E</p>

<ol>
<li><p>is it C? (kinda guess)</p></li>
<li><ol>
<li>Because the capacitor sucks up all the charge, so no current goes through R2 at the beginning.</li>
</ol></li>
<li><p>Because when the capacitor is full, the current goes into the one with the R2 resistor.</p></li>
</ol>