<p>^yeah you needed the ratio of the masses
and for the ice cubes:
it was the one with 2 flat regions and 3 sloping regions</p>
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</p>
<p>EDIT: Ohh i got the ice cube one wrong! >.< I forgot about the change in the form its in so temperature doesn’t change >.<
I agree with E for the two colliding masses, since you need to know their mass and it says the masses may or may not be equal</p>
<p>schoolisfun, yeah i got that too</p>
<p>what about the one with initial velocity 30 m/s, and it asks for final velocity and acceleration?</p>
<p>In the ice cube one it started at -50, goes horizontal at 0, then increases again, horizontal at 100, and then increases up to 150.</p>
<p>I put v1/v2 > 1 since object 1 stopped moving at the point of collision, and they said the collision “need not be elastic” which I interpreted as inelastic.</p>
<p>Yeah and i think the displacement was also zero. or was it the distance?? :P</p>
<p>I think final was 30 m/s and acceleration was -10m/s?</p>
<p>
What equation would you use for that?</p>
<p>I think the one with initial velocity 30 m/s asked about v and a at the top (0m/s, -10m/s2) and right before it hits the ground (30m/s, -10m/s2). I think it asked about speed and not velocity.</p>
<p>the object was launched straight up, so it has the same velo right before it hits the ground. and acceleration of gravity is -10</p>
<p>^for that question, do you remember if they threw in -30 m/s as a trick answer?</p>
<p>I dont think so. It asked for speed so it would be +30.</p>
<p>there was also one asking about two “things” (dont remember how they were called in the SAT) being placed next to each other till they reach thermal equilibrium. I didnt have a clue about the answer and ended up guessing the one that said that entropy increased in the system or something like that.</p>
<p>^Yeah I guessed the same thing lol</p>
<p>Compiled Answers
-Universe expansion: red shift + something else, I & II
-Oil drop: calculate electron charge
-Ice cube -50 C to 150 C:
… _<em>/
… /
.</em>/
/
-X and Y collision: need to know masses (was this the same as ratio of the masses?)</p>
<p>“I dont think so. It asked for speed so it would be +30.”
^But was -30 even one of the choices at all?</p>
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<p>I think I just realized I got it wrong. I assumed mass 2 > mass 1. Did they say that, or just unknown masses?</p>
<p>@Jimei1337 dont think so
@MCS735 i remember they even said “unknown masses”, so i guess so.</p>
<p>I put entropy increasing as well ^</p>
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<p>I believe it was unknown masses, can anyone confirm?</p>
<p>almost 100% sure they were unknown</p>