<p>Can you guys post any link for AP Physics B exams online? Any good multiple choice test will do? Even review. Please!</p>
<p>Electrical Potential Energy, = qE(displacement), right?
and then what is Electric Potential? V = kq/r?</p>
<p>Can anyone explain the difference to me, please?</p>
<p>Think of it in terms of gravity. Electric potential energy is gravitational potential energy or mgh and equals (k * q1 * q2)/r. Electric potential is voltage and is an actual force which equals Ed.</p>
<p><em>cries</em> can u elaborate on why the magnetic field never does work...?</p>
<p>"A magnetic field of 0.1T forces a proton beam of 1.5mA to move in a circle of radius 0.1m. The plane of the circle is perpendicular to the magnetic field.
-- Of the following, which is the best estimate of the work done by the magnetic field on the protons during one complete orbit of hte circle?
0J << answer
10^-22J
10^-5J
10^2J
10^20 J"</p>
<p>maverick: Work is only applicable when parallel to the direction of the force. [aka, If i push a block, I'm doing work (my force is to the right, it's moving to the right) If i held a block and moved to the right, the work would be ZERO because my force is Up [holding the block up] but I'm not PUSHING the block to the right. It's direction of motion and the direction of force is not parallel to one another. WORK IS ONLY THERE WHEN FORCE AND DIRECTION ARE PARALLEL.]</p>
<p>Now the question says: "A magnetic field of 0.1T forces a proton beam of 1.5mA to move in a circle of radius 0.1m. The plane of the circle is perpendicular to the magnetic field."</p>
<p>The B-Field is moving the proton PERPENDICULAR to the B-Field, therefore, work is equal to zero.</p>
<p>Let's try this, since I know sometimes I forget and get screwed...</p>
<p>Name the Units of each of the follwoing, or name what it equals.
Current = Ampere
Voltage = Volts
nanometers = how many meters?
microFarad = how many Farads?
Work = ?units (Force per distance = Newton<em>meter)
Energy = ?units
Force = Newtons = kg</em>m / s^2
Power = Watts = </p>
<p>Just add anymore.</p>
<p>Energy = eV or J (where 1 eV = 1.6 x 10^-19 J)
Magnetic Field = Tesla
micro = x10^-6
nano = x10^-9
milli = x10^-3 ?
Power = Watts = J/s
Impulse = F*t = Newton-second</p>
<p>anyone wanna share how to memorize lenz's law if you dont understand it.. this iswhat i know so far</p>
<p>if B is into page and a coil is entering a field current is counterclocwise. if its leaving, then its clockwise
if B is out of page, and a coil is entering, current is clockwise, if its leaving, its counterclockwise</p>
<p>who is pumped for tommorow?</p>
<p>i'm still reviewing the Princeton Review AP Physics book... it's so damn big. I'm on magnetism... i'm EFFED. =</p>
<p>its good its at 12, more time to cram</p>
<p>"who is pumped for tommorow?"</p>
<p>I was more pumped about a weekago. Now I am just dragging myself to a close.</p>
<p>Calc BC self-study - this was my easiet exam, it should have been my hardest.
Physics - I actually took the class, and I am still going to underperform.</p>
<p>So what are you listening to? Me: Linkin Park and Green Day! :)</p>
<p>I'm in Sagar's class and we didn't learn anything this year.</p>
<p>But I went through all of PR yesterday and today. So I'm cool.
At least I have some concept in my head. lol</p>
<p>You know what... I'm positive I will get at least a 2 :)
Maybe even a 3 if I'm lucky.
Heck a 4 isn't that far out of reach.
And well a 5 is blah lol </p>
<p>What am I doing? Telling the tennis champ in my class that the test is not just on kinematics lol</p>
<p>michael_pham: Well, if the test was only on kinematics, I think we'd all end up with 5's!</p>
<p>Haha yeah </p>
<p>This kid in my class who is usually never in class is the tennis champ for our county and only knows up to kinematics lol
I told him to memorize all the formulas, since he hasn't studie and he said what are all these weird symbols lol</p>
<p>Lol sounds like the tennis champ in my class, he's like 1st in county, 5th in state or something like that, and doesn't study much.</p>
<p>hope frq will be easy</p>
<p>So do i. If it's not, i'll be effed</p>
<p>its coming so soon ahhhhh lol</p>
<p>1.5 more hours</p>
<p>1 hour for me lol</p>