June 2008 - Physics

<p>well, in my case the 2.5 came from me thinking "well, with gravity there's always some kind of inverse-squared relationship, so maybe 2.5^2 = 6". i'm hopeless without my calculator.</p>

<p>Yikes, I think I got like a 51 composite. Hope it's over 700 so I never have to see that test again!</p>

<p>how is it a horizontal straight line for the electric field with plates?? what did the question ask exactly??? because the way i thought about it was i knew that V=Ed so then E=V/d so therefore Electric field is inversely proportional to distance between plates..... someone prove me wrong or affirm what i said or did i misunderstand that question???</p>

<p>stueydue: what was the question? Lighten me up~</p>

<p>wavvy that was one of the match the question to the graph problems from the start of the test.</p>

<p>there was some other question i'm pretty sure that F normal = F perpendicular and F parallel = frictional force or something along those lines</p>

<p>stueydue: Think of an infinite charged plane and use Gauss's law to prove that E = sigma / (2 epsillon naught). Two oppositely charged plates imply E = sigma/(epsillon naught) independent of distance between the plates. </p>

<p>What was the conclusion on the convex lens on plane question? refraction or interference? </p>

<p>Was the 9/10 speed of light question D? sorry I was confused by an earlier post regarding that and needed to clarify.</p>

<p>wavvy, i need someone else to state explicitly what the question said, but from what i remember is that it was at the beginning and it said that which graph shows the relationship between an Electric field and the distance between the plates... thats what i thought, and then you can see what i did thinking like that in my post above. but some others are thinking its a horizontal line and i think i may have read the question wrong or am an idiot</p>

<p>wewet234:</p>

<p>Interference.</p>

<p>Length is shorter, but not zero.</p>

<p>What about the one with the PVT curve? I don't think anyone has mentioned that yet...</p>

<p>okay, so wewet, why is what i did wrong if your way is right??? and i thought sat physics didnt test gauss's law....</p>

<p>For PVT curve, I reasoned that there is no change in internal energy if there is no work done (aka, 0 area under the curve). This is for segment B. </p>

<p>Anyone care to confirm/reject?</p>

<p>stueydue: ah I remember that question. For that matter I'm with wewet234.</p>

<p>rupac, internal energy is 0 when its an isothermal process. thus, seg C
and can someone explain why the positive charge going through the two plates will go parabolically upwards as opposed to in a circular motion upwards???</p>

<p>stueydue: to get a circular motion, you need to have a component of F perpendicular to v. ie, the direction of F keeps changing with respect to time. In this case, F always points upward. It is like...and upward PROJECTILE!!! (the magnetic force here is like the gravity)</p>

<p>Physics was so easy guys. I think i got 0 wrong.</p>

<p>well, stueydue, if u look at the graph:</p>

<hr>

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<p>+
++++++++++++++++++++++</p>

<hr>

<p>the positive charge is attracted to the negative charge and the positive plate pushes the charge up...just imagine it moving and eventually, over the distance, it has to move up parabolically...if it moved in circular motion, it would probably bumped into the negative plate before it can get out of the plates....i hope my explanation is ok...
and i picked D for PV diagram...it was a guess and based on my memory @ the book I've read on physics. but i'm probably wrong on that one....</p>

<p>did anyone remmeber the question about a block on a curved ramp. the first question was about which of the following values decrease..i picked potential energy, not normal force and the sum of potential energy and kinetic energy</p>

<p>the second question on that asked which values increased, so i put the normal force only as the value that increase....not PE or the sum of PE and KE, since energy is always conserved and potential obviosuly decreased as the block slides down the ramp (i think, frictionless).
so could anyone tell me if i got this right?</p>

<p>You are a BIG LIAR!</p>

<p>it was segment C the segment on the isothermal curve</p>

<p>and hey, it's entirely possible to get -0 lol! the test has a cieling u know=]</p>

<p>keep shootin more questions and answers.
i would like to know what i got, well actually, i just want to know if i could make an 800 or not lol
so far im at 63/75 (4 omit, 6 wrong)
is that an 800?</p>

<p>Not "this" particular test!</p>