<p>For the pulley question I remember first putting down W. I reread the question and realized it asked for the string holding the pulley. Therefore the answer is 2W</p>
<p>boiling water and open container, the vapor pressure has to be equal to the atmospheric pressure (this is more of a chemistry question but whatever). If you draw a phase diagram, you'll see that the liquid/gas equilibrium line lies at temperatures where the vapor pressure of the liquid (water) at this temperature is equal to the atmospheric pressure. This is also why water boils at a lower temperature at high altitudes where there is little atmospheric pressure.</p>
<p>i sort of remember the n/s pole magnet question, and I believe the answer is "the material can be magnetized." the two south pole/two north pole things make no sense at all, since if the material is uniform (safe assumption), what would the magnetic field lines look like if there were 2 south poles at the end? it would be really crazy.</p>
<p>Does anyone have any other questions? We're still missing around 20.</p>
<p>What did people get for the problem involving a sound wave? I put it couldn't be polarized.</p>
<p>What was the guitar string problem? I don't remember it.</p>
<p>For the three rotating wires, I got all three I think because my visualizations for each showed the wire cutting the magnetic field. Can someone clarify this?</p>
<p>The pulley question:The answer is 2W because:</p>
<p>The forces in the y-direction have to cancel each other out because system is in equilibrium. So the forces acting down are W and W. and the top force is T. so T = W + W. therefore T = 2W. Agree?</p>
<p>aznarchmage Yes I got the same thing</p>
<p>but others are saying that it was only 2 of the 3</p>
<p>Me too. I got all 3. I evn used the hand rules to make sure there was a induced current and force (cus flux). But like Kian said, others are saying 2 and 3. I am almost POSITIVe that the pulley one was W not 2W. I even asked my teacher. He said it was most probably W if it involved the strings.</p>
<p>ru4real1666: Explain adequately why u think the pulley question was W and not 2W.</p>
<p>what is this about a problem about a sound wave? i dont remember...</p>
<p>the three rotating wires was only TWO. Flux or induced current requires that there be a change in magnetic field. In the first two cases there is a change because the angle between the wire loop and the magnetic field lines is always changing. For the third this angle is constant because the axis of rotation of the loop of wire is parallel to the magnetic field lines. Thus, no induced current for number three.</p>
<p>what does polarization have to do with sound waves at all? Sound is a longitudinal (compression) wave... is polarization even relevant? Gosh I dont remember that q at all...</p>
<p>guys chillax...im sure the curve will be adequate.</p>
<p>oo was the sound wave question "wat accounts for the difference in interference pattern between sound and light wave"?</p>
<p>in that case, answer is wavelength...</p>
<p>ucrotcpaplc: yes, the answer is wavelength. That's what i put...hopefully its right.</p>
<p>it has to be... cuz the equation is</p>
<p>wavelength/d = x/L, and so the only value in there that's relevant is wavelength</p>
<p>If the pulley question were asking about the string holding the pulley, wouldn't the mass of the pulley complicate matters? Does anyone recall it specifying a "frictionless, massless pulley"?</p>
<p>I may be in denial, but I'm pretty sure that it was asking about the string between the weights.</p>
<p>yes, it did say frictionless, massless pulley. but it was asking about the string holding the pulley.</p>
<p><em>bump</em><br>
wanna hear more</p>