<p>is the 2010 AP Physics B multiple choice a completely new test since the released the 2009 multiple choice?</p>
<p>^^^Okay, to do this you need to know that closed tubes (that’s what the water does) resonate at 1/4wavelength, and odd harmonics after that. Let w = wavelength</p>
<p>3/4w - 1/4w = .5 m
1/2 w = .5m
w = 1m</p>
<p>so v = fw
f = v/w
f = 340 / 1
f = 340 Hz
(just checking, can someone confirm the answer?)</p>
<p>^^ The flux is changing in the direction of the magnetic field so the current has to flow opposite the change. This is when your fingers curl downwards, and when your fingers curl downwards, the thumb points to the current which is counterclockwise.</p>
<p>it counterclockwise because the b field is decreasing so the current would want to increase the b field outward. the rule of thumb for lenz law is that it opposes what ever is goin on.</p>
<p>tito, you’re right.</p>
<p>Tnyn - I know that it opposes, but how do we know that it’s counterclockwise? When I do the right hand rule (thumb is current, fingers are field, and palm is force), it tells me that the current should be clockwise.</p>
<p>Here, it is once again:</p>
<p>^ The flux is changing in the direction of the magnetic field so the current has to flow opposite the change. This is when your fingers curl downwards (because the field is changing upwards), and when your fingers curl downwards, the thumb points to the current which is counterclockwise.</p>
<p>For those people that want to take the 2004 exam:
Here are the questions: [Powered</a> by Google Docs](<a href=“http://docs.google.com/viewer?a=v&q=cache:gkckhs9rG3AJ:www.arlington.spps.org/sites/3ccf4ac7-d146-48dd-95e6-0a0073e5ce1a/uploads/Bmc2004.pdf+ap+physics+b+2004+multiple+choice&hl=en&gl=us&pid=bl&srcid=ADGEEShyJeiwIzBA-ZG9HMGE6tngCdAS-1ThHbMRNDS9kOvr3Bgvx_vLMQznnr0y-Wrp5tYcsJjmrw9nF6wM3TQn1MCoRoTmuZ1aKMFEddAj7KICPcwOIrjW_F20Rwio37OJ3v1pzNIK&sig=AHIEtbT6nlHLvJ6SutxIoA3VmsQmRA613g]Powered”>http://docs.google.com/viewer?a=v&q=cache:gkckhs9rG3AJ:www.arlington.spps.org/sites/3ccf4ac7-d146-48dd-95e6-0a0073e5ce1a/uploads/Bmc2004.pdf+ap+physics+b+2004+multiple+choice&hl=en&gl=us&pid=bl&srcid=ADGEEShyJeiwIzBA-ZG9HMGE6tngCdAS-1ThHbMRNDS9kOvr3Bgvx_vLMQznnr0y-Wrp5tYcsJjmrw9nF6wM3TQn1MCoRoTmuZ1aKMFEddAj7KICPcwOIrjW_F20Rwio37OJ3v1pzNIK&sig=AHIEtbT6nlHLvJ6SutxIoA3VmsQmRA613g)</p>
<p>And the answers: <a href=“http://www.pdfarama.com/preview?view=aHR0cDovL3d3dy5jYXRoZWRyYWxocy5vcmcvcGh5c21hdC9QcmFjdGljZTFfTUNfQUtleS5wZGY=[/url]”>http://www.pdfarama.com/preview?view=aHR0cDovL3d3dy5jYXRoZWRyYWxocy5vcmcvcGh5c21hdC9QcmFjdGljZTFfTUNfQUtleS5wZGY=</a></p>
<p>On the free response, are we expected to keep our units straight through the entire thing? Or can we just stick it in at the end. Are units even important on the rubric? (Our teacher insists that the concepts are more important than stuff like this…)</p>
<p>When you do the right hand rule, you know the force is outward and the magnetic field is out of the page… and treat each part of teh circle as its own straight wire. If you use the rule on the right of the wire the force will be up, down on the left, etc making it counterclockwise throughout the whole thing.</p>
<p>A boy of mass m and a girl of mass 2m are
initially at rest at the center of a frozen pond.
They push each other so that she slides to the
left at speed v across the frictionless ice surface
and he slides to the right as shown above. What
is the total work done by the children?</p>
<p>Need help on this problem. Answer is 3mv^2.</p>
<p>(1/2)(2m)v^2(girl’s KE) + (1/2)(m)(2v)^2(boy’s KE) = mv^2 + 2mv^2 = 3mv^2</p>
<p>Boy’s velocity can be found by action/reaction pair.</p>
<p>Total work is the change in KE
So:</p>
<p>KE is initially 0</p>
<p>After pushing the speed of the boy is:
mB = 2mv</p>
<p>B = 2v</p>
<p>so total KE is 1/2(m)(2v)^2 + 1/2(2m)(v)^2</p>
<p>KE = 1/2(m)(4v^2) + 1/2(2m)(v^2)
KE = 2mv^2 + 1 mv^2
so KE = 3mv^2</p>
<p>This equals work according to the work energy theorem</p>
<p>^Oh, that makes so much sense. Thx a lot.</p>
<p>just wanted to say… good luck everybody!! 
sleep well, good breakfast, top shape in the morning woohoooo</p>
<p>Does anyone have some practice half atwood and atwood problems? Oh, and some banked road too…
I suppose I could search through every part II the past 10 years but if anyone has a compilation of problems that would be SUPER cool</p>
<p>Lol, I got the Princeton Review 2009 from my friend’d brother at about 6:00 PM today. Started writing down the chapter summaries, then gonna wake up early and study tomorrow.
Test is at 12:00, honestly expecting a 1 or 2, hoping for a 3.</p>
<p>Yep good luck and good night everyone :).</p>
<p>are we required to keep units throughout the entire FR? Or are units at the end sufficient?</p>
<p>You should have proper units for every subsection. Your best bet is to use the right units just in case they might penalize you.</p>
<p>also May someone clarify the concept of potential difference? Especially in FRs where there is an electron beam passing through two plates of different potentials, making the beam go upward and the question wants you to figure out which plate has higher potential</p>
<p>I hate AP Physics B. I suck at it so much. Now i have to depend on the FRQ to get a 5. I would be alright with a 4 :(</p>