MAY 2013 PHYSICS THREAD (question pool)

Test Preparation SAT Subject Test Preparation
41

<p>^piquantpeppers glass. index of refraction. I think… Not positive, Cuz I never took the Physics B course, so I’m not really familiar with the optics stuff</p>

42

<p>index of refraction is least for red (learned this in class literally last week holla)</p>

43

<p>@jansatomg
Yeah I think that’s right</p>

<p>Can someone confirm solipsisme’s questions because I was unsure of those also</p>

44

<p>I put 1:1, my friend says 2:1.
Guys the magnet one was the current REVERSES direction by lenz’s law. I’m pretty dang confident about that.
And the pipe one was 50 Hz.
And the ball goes tangentially when it comes out, so it’s B. I’m definitely sure about that one.</p>

45

<p>^ I second Miami24</p>

46

<p>thanks Miami24!</p>

<p>agreed with you and not your friend-- i’m 99% positive it’s 1:1, looking at <a href=“http://images.tutorvista.com/content/waves/closed-pipe-vibration-modes.gif[/url]”>http://images.tutorvista.com/content/waves/closed-pipe-vibration-modes.gif&lt;/a&gt;&lt;/p&gt;

<p>since the fundamental freq has 1 node, 1 antinode => 1:1.</p>

47

<p>^Miami. For Lenz’s law, the b field is always opposite. So when the N side is in the solenoid, for the b field generated by the solenoid, the N should be in the left. When the S side is in the solenoid, the S side of the b field generated by the solenoid will be in the right. For both situations the b field didn’t change direction…</p>

<p>That’s what I thought… I could be wrong, since I didn’t learn the E&M stuff really well</p>

48

<p>Does anyone remember the question that asked about the magnetic field lines for a circular wire that went into a page?</p>

49

<p>@kmb <a href=“http://3.bp.blogspot.com/-MRe27IlZtbw/T8In6n6CkUI/AAAAAAAAAAo/G1fSNsRMbNU/s320/Showing+Magnetic+field+lines+(magnetic+lines+of+force).jpg[/url]”>http://3.bp.blogspot.com/-MRe27IlZtbw/T8In6n6CkUI/AAAAAAAAAAo/G1fSNsRMbNU/s320/Showing+Magnetic+field+lines+(magnetic+lines+of+force).jpg&lt;/a&gt;&lt;/p&gt;

50

<p>What was the answer for the question where someone was doing 6 trials of freefall and recording the time for each trial? Measurements were like 40s, 40s, 40s, 41s, 42s, 43s and the question asks u which time the experimenter should choose?</p>

51

<p>^wlsnehf I believe that one is 4.1, just find the average of those.</p>

52

<p>I put that too, so finding the average is correct?? Some people said 40s because it appeared 3 times…</p>

53

<p>^wlsnehf According to my lab experience… Finding the average should be impeccable at least… You could neglect some points however, but those has to be really far away from the expected value</p>

54

<p>No it has no effect on the gravitational force, because the distance is between the CENTERS of the planets, which of course does not change. Since the mass also does not change, this leaves the gravitational attraction force unchanged.</p>

<p>Choice B I think it was.</p>

<p>Also, how did you do the thermo question with rate of change of heat to get that 8 * 10^5 J/hr answer?</p>

55

<p>Im pretty sure that I failed this test. :(</p>

56

<p>do you guys agree that this test was harder than practice tests,? I’m hoping for a lenient curve…</p>

57

<p>For the thermo one I estimated the slope at that point to find deg C/hr which was 8<em>10^5 I think, then 10J/deg C to get 8</em>10^6 J/hr. For the one about the form of equations, did anyone else get y = k * x for both?</p>

58

<p>^kmb987 y=kx, I got for both as well.</p>

59

<p>@independent explained in post #29</p>

60

<p>Yeah it’s y = kx for both. Err I got 18 * 10^6 J/hr. I had no idea how to do it. #PhysicsCproblems</p>

<p>@solipsisme: Thanks. Didn’t see it.</p>