<p>Haha, the same happens to me. its a relief to know it was not on the test, even though I know Ive already screwed up. I knew it wouldnt be a good idea to learn all the physics stuff in just one month, because i think in the US they must have like 4 years of physics or something. :P</p>
<p>Compiled Answers
-Universe expansion: red shift + something else, I & II
-Oil drop: calculate electron charge
-Ice cube -50 C to 150 C:
… <strong>/
… /
./
/
-Initial velocity 30 m/s, v and a at apex: 0 m/s, -10 m/s^2
-Initial velocity 30 m/s, v and a final: 30 m/s, -10 m/s^2
-X and Y collision: need to know masses (was this the same as ratio of the masses?)
-Thermal equilibrium: increase entropy
-Insulator/conductor: glass and aluminum
-Starting a fire: converging lens
-Cop car moving: fA < f0, fB > f0
-People moving: fA > f0, fB < f0
-Heavy ball versus lighter ball: I put ratio of V to SA was smaller in the larger ball
-Lightest particle: electron (I just googled this)
-Magnification of diameter of coin: 6 (choice A)
-Ball going east, force applied to it: went east, curved, and carried on this way diagonally southwest
-Why doesn’t moon crash into earth: Constant gravitational pull, but the velocity keeps it from crashing
-Electroscope, what was the rod’s charge: negative
-Which one didn’t have a 1/r^2 graph: potential energy of charge
-Maximize magnetic force: I, II, and III (velocity of particle, charge of particle and magnitude of magnetic field)
-Moon and earth gravity, change in mass: no change (arghhhh I got tricked T.T)
-Moon and earth gravity, change in force: 160 N
-20 ohm and 40 ohm resistor: h/2
-Changing induced current: I, II, and III (area, resistance, rate of change of field)
-Charge and circle, change in potential: I and II
-Charge and circle, MAX change in potential: I
-Charge and circle, no work: III
-Two samples: 50 degrees C
-Buzzing noise: ???
-P/V graph for heat engine: II and III
-Normal force: cart on the bottom (point A)
-Scientist: Galileo
-2m and 3m carts: tension is 2m
-Greatest normal force on cart: at bottom
-Greatest acceleration for pendulum: at the greatest displacement (missed this one )
-Greatest tension on swing: at the bottom
-Index of refraction: ???
-Set of numbers, accelerating: 1, 4, 9, 16
-Set of numbers, force opposing velocity: numbers decreasing
-Set of numbers, K.E. of sliding block: 1, 4, 9, 16
-Inelastic collision: mech e and linear momentum conserved
-Guitar string: wavelength only
-Charge with highest potential: the one that was farthest up
-Which refraction/reflection line is incorrect: the one at the bottom going through the glass out into the air (choice E)
-Double earth radius, effect on gravity: g/4
-Change in pendulum period due to change in gravity: 1st planet would be sqrt(2)*T and in the second T/sqrt(2)
-Stretched spring = 2d, new velocity: 2v
-Frequency of beats: just subtract the 2 frequencies
-Impossible standing wave: the one that was impossible was the one where the nodes and antinodes were not in their places
-Rocket and earth relativistic speeds: Earth’s time is longer
-31 atomic mass: 16 protons and 16 electrons
-Slit experiment: there are dark and light intervals because light interferes with other light rays coming from different parts of the slit
-Heat engine: 110 J
-Free body diagram:
………N
………↑</strong>
FR←l__↘l
…………↓….F
…………mg
-Was there also a question where they gave you the wavelength of light and you had to calculate the frequency? 2<em>10^8 Hz (Was this on the test? I don’t remember this question.)
-Skewed elliptical orbit: angular momentum is conserved (III only)
-Calculate internal heat: II and III only (specific heat and mass)
-Force vs. Time graph, find impulse by calculating area underneath: 10
-KE vs. time: none are constant
-KE vs. time, when is velocity = 0: when graph intersects x-axis
-KE vs. time, when is velocity constant: when the graph is flat
-Election through magnetic field, force = 0: when electron was moving parallel to the field
-Election through magnetic field, force going upward: electron moving left, field pointing out of page
-Three of these make up something in the nucleus: quarks, 3 quarks make a proton
-Number of electrons/second in 1.6 A current: 1</em>10^19
-Angle to maximize magnetic force: 90 degrees
-Convection: I remember the answer being the only one with gases and liquids mentioned in it? Can anyone confirm?
-Proton in middle of two particles, charge of two particles: both negative
-Parallel plates: ???</p>
<p>Total: 67 (there were some overlaps, and only 64 are have actually been answered)
Read through ALL of these (some of the earlier ones may have been changed) and see if you guys agree. Also, see if you have answers to the ones with question marks.</p>
<p>I think the oil drop was for electron levels. The answer had something to do with multiples.</p>
<p>There was also one asking about what was NOTa property of sound waves. One option was, they reflect at the same angle of incidence. There was also one that said that they could be polarized when going through polaroid disks or sth. like that. Does anyone know the answer?
Does any1 still know what the question about parallel plates was about?</p>
<p>^I think I put polarization for that one since light waves get polarized
number 9
[SparkNotes:</a> SAT Physics: Explanations](<a href=“SparkNotes: Today's Most Popular Study Guides”>SparkNotes: Today's Most Popular Study Guides)</p>
<p>I put polarized.</p>
<p>One of the parallel plate questions was which one feels 0 force or something like that. I put the middle one.</p>
<p>I THINK I put polarization for the sound one. I sure hope I did, at least :-/</p>
<p>^I don’t remember one that asked for which particle felt a net force of zero. Are we talking about the parallel plates that had opposite charges and had 100V going through it?</p>
<p>No, they were particles.</p>
<p>I know there were particles between the plates, but all of them had to have experienced some force. I’m afraid I don’t understand which question we’re talking about.</p>
<p>O O O
3 particles as above. they are in equilibrium. When u take the first particle, then the middle particle is attracted towards the right one.</p>
<p>Oh yeah. I think someone already answered that one. I can’t remember the charges, but the two charges on the end were the opposite of the one in the middle.</p>
<p>I remember there were two parallel charged plates of opposite charge with 100V running through them, creating an electric field. Then there were particles in between them, and it asked a couple of questions about it, including which one felt the largest force and what the force was. I think the correct answer was that they all felt the same force, but I can’t remember the other one. Anyone remember these? I don’t see them on the answer compilation.</p>
<p>I still hold fast to my claims that the buzzing sound problem was fundamental frequency, and not resonance.</p>
<p>I would really like to have an explanation about the question on the inellastic collision. I have just read that in perfect inellastic collisions, the kinetic energy is transformed in heat and sound energy, and potential energy to a lesser extent. So, if not all of the KE is transformed to potential energy, then mech. energy would not be conserved, since:
Mech E. = KE + U</p>
<p>:P</p>
<p>And I remember another one. It was about a graph of displacement vs. time. It was an inverted parabola. The questions were what was the velocity of the (car) in the middle of the time interval? Answer was zero, since the tangent line through the apex had a slope of zero.
The other question was about the total displacement of the (car), which was zero, too, since the average velocity was zero.</p>
<p>^^I second that. I don’t think mechanical energy is conserved. I remember my physics teacher making a big deal about the fact that inelastic collisions never conserve kinetic energy; only linear momentum. I think that ought to be changed.</p>
<p>^Yes and yes to both of those. We’re almost done!</p>
<p>^and btw, the buzzing sound is due to beats of the different frequencies of the speaker which destructively interfere.
^^^yes, they all felt the same force, cant remember the other question though.
PD: sorry for my bad english, im a student from Bolivia ;P</p>
<p>^Are you sure about the beats? That’s what I had n that would be a relief if that was the right answer! :)</p>
<p>Im not 100% sure about that, i hope it is :)</p>
<p>^Have you found anything on it online? lol</p>
<p>By doing research online Ive found out that u can score a 800 by omitting 16 questions. That means a raw score of 59 would still be 800. yay!</p>
<p>It could very well be beats. I’m still unsure. Beats occur when two frequencies come really close to one another (like within a few hertz) and creates a sort of pulsing sound. Musicians use beats to tune their instruments, because the speed of the pulsing beats slows down as the frequencies get closer to one another. I just can’t imagine that this phenomena would be responsible for the buzzing sound in a speaker, since one speaker isn’t necessarily emitting two nearly-similar frequencies.</p>
<p>I picked fundamental frequency because every object has one, and when another wave with the same frequency hits the object, it caused the object to vibrate. The question read something like “when the speaker hits a certain pitch, it buzzes”. I interpreted this to mean the speaker was emitting a frequency equal to its own fundamental frequency, causing it to vibrate, or “buzz”.</p>