<p>Ya, thats what I thought too knavish. :)
Anyone get that too......</p>
<p>The question asks which of the graphs that can't be the condition of the rope at that particular instant. It may look like a straight line, but it has to happen at another moment of time than the one when the original graph was taken.</p>
<p>smiffer88 and knavish i agree... thats what i put, all the others, except the line, had 3 places where the derivatives are 0, the correct answer had 4</p>
<p>Yeah, I think I got a really stupid question wrong.. The momentum one. The question about the inelastic collision was ****ing me off.. I couldn't get the answer.</p>
<p>The intial momentum was 3(2)+6(2)=18.. right? The inelastic final velocity is 18=4v.. v=4.5 Isn't it?</p>
<p>Asbereth, I interpreted the question differently. I thought it was asking at any instant... I dont see how it could have two bumps, looking at the original picture. I could be wrong tho...</p>
<p>
[quote]
I thought it was asking at any instant... I dont see how it could have two bumps, looking at the original picture. I could be wrong tho...
[/quote]
</p>
<p>The picture shown is just part of the entire thing. In its entirety, it may / may not have two bumps. That aside, it would be impossible for a standing wave to be partially a straight line, while, on the other part of it, it isn't. </p>
<p>
[quote]
The intial momentum was 3(2)+6(2)=18.. right? The inelastic final velocity is 18=4v.. v=4.5 Isn't it?
[/quote]
</p>
<p>I think momentum takes direction into account.</p>
<p>i think smiffer is right... the wave would be uniform throughout the length of the wave.. if it is asking which cant be it, then it would be all of them because they arent the same as the original wave.. it has to be which cant be the rope at any other period of time. and the one with two bumps is the answer.... i think</p>
<p>Knavish, for the inelastic one i got...</p>
<p>2(6)+2(-3)=4v
v=1.5</p>
<p>One of the V's has to be negative because there going in opposite. At least I think thats right. Anyone else get that???</p>
<p>Oh my.. damn it.. I knew momentum was a vector. It feels like I blanked out today.. Maybe it's because I was sick. What luck.</p>
<p>yea it was 2(3)+2(-6)=2(-6)=2(x) x=3 m/s
and then kinetic energy was 2*0.5(9+36)=45 J
and i also got 1.5 for the inelastic one too</p>
<p>there was a question about where momentum is conserved. it was all conditions, right? an elastics collision, a completely inelastic one, and a spring between two blocks</p>
<p>Again, as I said before, the picture shown in that question is just part of the entire thing. The rope could have infinitely many bumps, but if you only took a picture of some section of it that only has one bump, it wouldn't show the remaining in the picture. Ah well, I don't know how to explain it any better. Writing coherently has never been my forte.</p>
<p>do you have to memorize all the equations for the Physics test?
is the test hard?</p>
<p>momentum was conserved in all three because... well momentum is ALWAYS conserved... :) i spent a few minutes on that and thats what i came up with.</p>
<p>Yes, the conservation of momentum question was all conditions</p>
<p>ok and that's b/c mv\0 at the begining and the blocks go in opposite directions so mv+m(-v)=0</p>
<p>are you allowed to use any calculator (TI-83 plus)?</p>
<p>Did anyone get #74? Where is the greatest electric force applied at? (or was it magnetic field??) It was just a diagram question with points A,B,C,D,E placed on the outer region of a closed wire.</p>
<p>I put at the point.</p>
<p>we discussed this earlier, i put D</p>
<p>sorry, but why is it D?</p>