*** Official AP Physics B Discussion Thread 2013-2014 ***

<p>it got rekked again, lost permissions</p>

<p>mcq about two charged/conducting spheres and x has more mass than y. was the answer something about the same potential or the same charge?</p>

<p>Sorry guys it was an accident :(</p>

<p>I was trying to set it to limit the powers of anonymous trolls but I accidentally screwed it up</p>

<p>I apologize </p>

<p>@sparkl you’re too vague</p>

<p>whatd you guys get for the MC’s with the circuit with 1 capacitor near the beginning of the test?</p>

<p>was like current immediately after switch is closed, and current after capacitor is charged</p>

<p>there are two conducting spheres. x has more mass than y. and if they are connected using a wire or something. what happens after a while? haha i dont remember exactly how it was worded</p>

<p>thats what i put sparkl</p>

<p>^</p>

<p>If they had different radii, then potential was different. But charge could be the same.</p>

<p>how many photons or something were emitted during the short burst of energy with like energy of 10^-18 J or something</p>

<p>Curve predictions, higher or lower than 2009 <a href=“http://appass.com/calculators/physicsb”>http://appass.com/calculators/physicsb&lt;/a&gt; ?</p>

<p>@Unununium‌ a lot of my friends thought the MCQ were really easy but the FRQ was pretty difficult. I think that it might be like 3 points higher than 2009. I’m not sure though.</p>

<p>Was the answer to the segment BC?</p>

<p>Okay but ■■■ was that PV diagram, work done by a gas is known as negative work lol. So idk where work done by a gas is positive.</p>

<p>^^ I thought of it like a double negative. Work done BY a gas is negative and multiply that by a positive and it’s still a negative. I think they were just trying to trick kids. </p>

<p>So what do you think the answer was?</p>

<p>I was tricked<~
But at the beginning of the info sheets, it said w=work done on a gas as negative… So if it’s by the gas, wouldn’t it be the opposite? </p>

<p>Another document ruined.</p>

<p><a href=“https://docs.google.com/document/d/1HITS9NgOCPHfK4_FKUMfdWtM5NInXipNDs-fGvqXKV4/edit?disco=AAAAAHYC_n8”>https://docs.google.com/document/d/1HITS9NgOCPHfK4_FKUMfdWtM5NInXipNDs-fGvqXKV4/edit?disco=AAAAAHYC_n8&lt;/a&gt;&lt;/p&gt;

<p>At the risk of having my score ruined, I’ll tell you all the answer</p>

<p>This PV diagram’s cycle was moving clockwise. Process AB was isothermal, thus no work is done. </p>

<p>BC was isobaric, but it’s arrow was pointing to the right, meaning it is travelling clockwise. Work is negative on a PV diagram if it travels clockwise.</p>

<p>CD was also isothermal, again no work was done.</p>

<p>DA was isobaric, and it’s arrow pointing to the left. It is travelling counterclockwise. Thus it is doing POSITIVE work.</p>

<p>If I got any question right (and that’s not many…sadly), it’s this one.</p>

<p>RIP google doc. </p>