Official Nov. Physics Thread

<p>what did you guys put for the second question? the one with "what changes as the electrons strike the screen of the TV in the ray tube" thing?</p>

<p>fruitcake Its higher. 100% sure.</p>

<p>Kalamity: I think I put in potential or KE. dunno</p>

<p>it was either electric potential or KE. i put EP first then changed it to KE</p>

<p>oh, and wth was that thing with the brocolli and insect shape question?</p>

<p>Insect does not have a fractal pattern. Brocolli does. Atleast I think so</p>

<p>for the tv one.. isnt it ke? just like the same principle for producing xrays?</p>

<p>asteriod one was just the asteriod, because it's not moving relative to the spaceships thus it's the slowest (closer to speed of light = less length).</p>

<p>electron, I put kinetic energy because it's stopped/slowed by the screen so KE is lost</p>

<p>why will the scores come out only on the dec 1? don tell me to ask CB</p>

<p>Omg I think I put in Electrical option</p>

<p>ooh, then i got it right. i put that the insect doesn't have the pattern. yay!</p>

<p>I thought Brocolli was right. Fractal was someting so called "self-similar".</p>

<p>Fractal</a> - Wikipedia, the free encyclopedia</p>

<p>brocolli is fractal</p>

<p>Insect isnt :)</p>

<p>Way to go jhl! :D</p>

<p>i still wonder what's the answer to that asteroid qn..</p>

<p>I didn't take this test but I assume that you were supposed to answer to which observer the length will be the shortest, right?
There is a phenomenon called length contraction. The faster the object is moving (relative to the observer) the shorter it appears.
This is the exact formula: length observed = lenght*sqrt[1-(v^2/c^2)]</p>

<p>the answer to the tv/electron is that the electron looses KE im sure i asked my physics teacher......about the asteroid one...i think that the spaceship moving at 0.9c measures the asteriod as being longest...since as things aproach c they get shorter....therefore the spaceship moving at 0.9c will be the shortest and relative to it the asteriod will seem the longest...does that make sense?</p>

<p>actually i answered 0.9/o.8c because i know weird things happen when we approach the speed of light.. hahaha</p>

<p>lol jhl ;)</p>

<p>i put 0.8c as well, but now i'm thinking it might be the asteroid (because it is the longest in its own frame of reference isn't it?)</p>

<p>ya 0.8 c thats what i meant =p</p>

<p>The Asteroid question was on the Asteroid itself, I'm 100% positive. Objects appear shorter when you're moving relative to them by a factor of gamma; since the asteroid isn't moving relative to itself, it's the longest on it's own reference frame.</p>

<p>The screen hitting the TV was a loss of Kinetic energy; The loss of kinetic energy causes the atoms in the screen to become excited; I don't think it would be electrical potential energy because if the particle is moving in the direction of the field, the particle is always losing electrical potential energy as the field does positive work, not just when it hits and object. </p>

<p>I left the convection question blank (Radiation was the right answer I think), just because I couldn't remember if convection required a medium or not. </p>

<p>For the fractal, I know what a fractal is I just wasn't sure how to narrow it down and get the answer, because I've never studied real-world examples of fractals; I think the question was either insect or frost, I put frost but I think that's wrong. </p>

<p>For the last question, did you guys get E? (3600 w/e); Also there was a question with a block being pushed by a force; it asked what would be an equivalent expression for the work, was it I and III only? (II was mgd, which wouldn't make sense because mg wasn't responsible for the motion), and I can't remember what option III was but I seem to remember thinking it was correct. </p>

<p>Also, on the question about a tree, did you guys get .25 m for the height of the image? and what was the optics question about the bird?</p>