<p>wavelength is the only one that stays the same because you arent changing the length of the string, so when it vibrates, the nodes will be in the same place, thus same wavelength.
frequency changes obviously, and if frequency changes but wavelength doesnt, then speed changes too.</p>
<p>
The question was a single slit.</p>
<p>^I believe the answer still involved constructive interference though, didn’t it?</p>
<p>I’m not certain if it was for that question, but I answered “interference” for one of them.</p>
<p>What was the answer for the heat engine one? 50 J of work done by pump and 60 J of heat absorbed?</p>
<p>^^My bad, it was single slit, however the answer remains the same</p>
<p>i was sure, but to me the diagram implied that the answer was 110J
if its not then i dunno how to get the answer at all lol</p>
<p>^^I think it was 10 J?</p>
<p>Because e= (Qh - Qc)/Qh</p>
<p>^I think the diagram of the heat engine was something like this:
PUMP----->ENGINE<-----COOL RESERVOIR (cant remember if this is how it was called). But according to the arrows of the diagram and the fact that the pump does work on the engine, and this absorbs heat from the cool reservoir, wouldnt be the answer 110 J??</p>
<p>Internal Energy= Q - W</p>
<p>It seems I misunderstood the question. I thought the pump did work TO the heat engine, increasing its total heat by the same amount. It seems it was the heat engine that was doing work to the pump. Thanks for clarifying. :</p>
<p>^ so whats the answer? and why?</p>
<p>Remember this one? Where u had a block on the ground and a force which was at an angle (theta) from the plane was applied to it, and it was asking about the diagram showing the correct direction of forces.
.F
….
___
……l___l</p>
<p>I chose this diagram:
………N
………↑___
FR←l__↘l
…………↓….F
…………mg</p>
<p>Hope u can understand it</p>
<p>Was there also a question where they gave you the wavelength of light and you had to calculate the frequency? I can remember very vaguely a question where they told you the wavelength was 1,5 m (not sure about the value, though), and the answer was:</p>
<p>2*10^8 Hz.</p>
<p>Was this question actually on the test?</p>
<p>@asianprotege
It depends on how was the question. If work was done BY the heat engine, then its 10J. However, if Work was done TO the heat engine, then it was 110J.</p>
<p>i think the question was:
engine does 50J of work to the pump
pump gains 60J of heat from cold resevoir
how much work did the pump do?</p>
<p>diagram was:</p>
<p>room
^
|
pump <– engine
^
|
cold resevoir</p>
<p>engine was actually on the other side of the pump, but thats irrelevant
90% sure thats what i saw xD</p>
<p>I honestly ignored the diagram.</p>
<p>@ Xanedrin. Yea I got the same thing for the free body diagram question</p>
<p>Hmm, I’m also quite positive that it was work done TO the system BY pump. For some reason I spent a really long time on that question. Very tempted to just put down 110 but it seemed too easy so I wasn’t sure. :\ Ah well…</p>
<p>Anyone have an idea of whether the curve will be easier or harsher this time?</p>
<p>Ughhh I spent like 2 days learning E&M. Needless to say, I was raped =.=</p>
<p>In the blue book, it says you can lose 16 raw and still get an 800. And the practice test wasn’t even that bad imo…so if its -16 raw for an easy test, would the curve for this test be even better? o.O</p>
<p>But I’ve seen -10 raw for an 800 thrown around a lot…where did yall come up with that?</p>
<p>Did you guys think this test was easier or harder? I thought it was pretty hard.</p>
<p>Most non-BB tests have their scales scored around -12 for 800, although it’s hard to say whether these curves are in any way indicative of the actual curve. That being said, I doubt the curve is as generous as -16. I can’t seem to find any relevant data about previous curves.</p>