<p>yep change in KE was 0 because magnetic forces can’t accelerate charges.</p>
<p>The test is brutal. Cant even finish.</p>
<p>@JustPhysicsThe one you wrote about the kE of the particle spinning, and this test was so hard…</p>
<p>@williypot</p>
<p>I concur on both accounts.</p>
<p>@williy @just</p>
<p>I also said change in KE was zero in the magnetic field.</p>
<p>The ‘zero & zero’ question was when the charges touched and one was grounded.</p>
<p>Why would the charge be zero? If it is grounded then electrons flow to the earth and it becomes positive and if it is touched with a positive sphere then it becomes positively charged.</p>
<p>@just I was under the impression that grounding something removed the excess charge no matter what sign it is.</p>
<p>Oh I think your right…that’s 5 wrong 5 omitted. Damn what is the curve usually like for this test?</p>
<p>Yeah grounding means removing the charge. so zero and zero is still the right answer.</p>
<p>Any other questions people can remember?</p>
<p>Oh the optics diagram: the image was shrunken and on the same side as the object. </p>
<p>What about those two rings with the current and the mag field? I put to the right…</p>
<p>The impulse was the change in momentum - that was a question.</p>
<p>Those 3 graphs about the block going up the incline</p>
<p>acceleration: constant slope
velocity: V shaped graph
displacement: upside down parabola</p>
<p>can anyone verify?</p>
<p>@injectmagic
I think that’s what I got…</p>
<p>Also kinetic energy is NOT a vector.</p>
<p>What about the two charged plates with the particles shot at different velocities to the right? I said they had the same charge.</p>
<p>@justphysics</p>
<p>yes to kinetic energy is not a vector and yes to same charge. :D</p>
<p>And what about the question that asked for the velocity of some particle going around the earth or something?</p>
<p>I did V = (2<em>pi</em>r)/T. Then it was like (2 * pi * (4.2 * 10^7) ) / (some T they made up). Did you get this and the previous questions injectmagic?</p>
<p>@justphysics i left that one blank because how the crap am i supposed to know the period <em>rageragerage</em></p>
<p>lol it was just random I think. They were testing to see if you knew to use the 4.2 x 10^7 as the radius, I believe.</p>
<p>The circuit for the total resistance of 6ohms had two resistors in parallel (one 4ohm and one 12 ohm) and then a 3ohm resistor. </p>
<p>Also did the light beam slow down when it hit the water?</p>
<p>@justphysics </p>
<p>there were 3 choices with 4.2*10^7 as the radius so you would have had to know for sure what the period is.</p>
<p>i got the same thing for that circuit resistance question.</p>
<p>and yes, light slows down when it hits the water.</p>
<p>@just The denominator was not random, it was (24)(60)(60) for the number of seconds in the day.</p>
<p>Yes, the circuit one is correct.</p>
<p>Yes, optics one is correct.</p>
<p>No, I checked that - there was only one choice with the correct radius they gave. I am almost positive because I was really confused at first but then I looked over the answer choices again.</p>