DECEMBER 2008 SAT Subject Test: Physics

<p>i agree with modernchem (about pendulum tension). What other mistakes did u see modernchem?</p>

<p>edited 10 char</p>

<p>I agree with bothof those modernchem</p>

<p>edited 10 char</p>

<p>What do you mean 6x? I put that [edit]. Did I overlook something really dumb? </p>

<p>OH WOW I can't believe I got the half life one wrong. Ughhhh stupid mistakes, they're killin' me!</p>

<p>I think I did surprisingly well considering I didn't know much about magnetism other than opposite charges attract LOL</p>

<p>^ The answer option was mass not weight, so it was wrong. I almost picked that too, what a low trick collegeboard!</p>

<p>SparkNotes:</a> SAT Physics: Pendulums</p>

<p>oh? wow, i can't do math.</p>

<p>On another note, I hate all true/false roman numeral questions.</p>

<p>It seriously said mass? OMGGG. fldsfjlksjfdlf</p>

<p>I'm gonna get out of this thread before I get more sad lol.</p>

<p>Posting discussions about specifics here probably isnt the best idea since technically you are allowed to and this is a public site. Im gonna edit my posts since my username is easily linked to my stats.</p>

<p>I thought the half life was 1 hour and 20 minutes. 3 half-lives from 96->12 in 4 hours => 240 minutes/3 = 80 minutes </p>

<p>The tension is highest at the bottom of the pendulum because T= F of gravity + force centripetal at that point. </p>

<p>Expanding universe - i put the doppler effect and the pervasive radiation. I didn't think elliptical orbit has anything to do with it. </p>

<p>Engine efficiency was 0.60 and 200J </p>

<p>Relativistic - I put greater than .6c but less than c. (debatable)</p>

<p>Our answers agree for the rest of the questions, I think. Things are really blurry in my mind right now.</p>

<p>relativistic was 1.2c so whatever answer fit that</p>

<p>half life was 1hr 20. 96 to 48 takes 1hr 20. 48 to 24 takes 1hr 20. 24 to 12 takes 1hr 20. 1hr 20 x 3= 4 hrs</p>

<p>it is so difficult to stay away from this thread!</p>

<p>modernchem, thats wrong, v can never be above c. i think i got that one wrong (i put .6c) but if its not .6c then its between .6 and c. </p>

<p>Was the pulley one W? Or 2W? </p>

<p>Was the heat dissipated H? Or h/2? Or 2H? I thought H bc v=IR and p=iv and h=pt... so v=i(.5r); p=i(.5v); h=(.5p)(2t) = h?</p>

<p>Well, one of the main ideas of the theory of relativity is that nothing can go faster than light. It can't be 1.2c
Both the particle and the spaceship are going pretty fast so we also have to account for time dilation and length contraction and such.</p>

<p>o and *** WAS the galvinator?? galvinator is not even on sparknotes.. and it has like 2 sentences in barrons... (yes you know how much extra stuff barrons has >.>) ..</p>

<p>and the induced current in wires was I and II? bc III doesnt change area perpendicular to B right?</p>

<p>I put 1/2h. Since the circuit was in series, the voltage splits. The total resistance was 60 ohms, so the voltage drop across the 20-ohm resistor was actually 1/3r if you want to approach it that way.</p>

<p>omg, i can't believe that my version of the SAT is just like the one you guys took. i took the test a full 10 hours before you guys (because of the time difference). if i had known i could easily have posted the questions on this site. im not sure of if collegeboard would have liked that lol!! (nor would this site ;) just kidding.
anyway, regarding the question about two objects with equal masses attached to the pulley. someone in this thread said tht the tension was 2W. but how can that be, the weights are equal and so the whole system is in equilibrium so the tension is each part of the string is equal to the weight (W). i dont think the question was referring to the string as a whole cause that wouldnt make sense both forces are in opposite directions and in 99.9999999999999999.... of the physics questions when we deal with a system of weights we are never asked for the tension in the "whole string"... obviously for a reason. as for the rest of the test it was really easy i missed three and made about three mistakes so im hoping for a 800 :D</p>

<p>I got half life = 1hour20min too. i just kept dividing until i got my answer. hopefully that's correct.</p>

<p>for the pulley with two equal masses on each side, the tension was 2W right?</p>

<p>For the pendulum, i put tension is greatest at its lowest point? not sure about that either.</p>

<p>What about the piano keys; what is greatest when you change the volume of the sound (louder/softer), but same note? I guessed amplitude...</p>

<p>^those idiots at college board.
and I think we may be thinking about different questions with the relativity.
and yes the amplitude is correct.
the tension is 2W, because it was the string holding the pulley. just their tricky way of saying 2 masses on a string</p>