<p>"I don't really understand E&M.
And I've got to cover fluids, waves, optics, and modern physics today. <em>sigh</em>"</p>
<p>Same here. I'm so screwed, I've only reviewed up to Friction on a Inclined Plane... and I dont understand anything about Electricity.</p>
<p>thats what i thought. hers the question</p>
<p>a particle oscillates up and down in simple harmonic motion. its height y as a fuction of time t is show in the diagram. at what time t does the particle acheive its maximum positive acceleration?
it starts at origin
at time 1 its at max amplitude but negative (5)
at time 2 its at 0 cm
at 3, max amplitude again, but positive</p>
<p>the answer is time 1.. how??</p>
<p>wow, I just did that q like 20 mins ago...anywayz,</p>
<p>The way I saw it was, when it's at time 1, it's at the lowest point going down. Therefore the acceleration is going upwards and is positive (whereas when it's at Y, it's at its highest point up and will accelerate downward in the negative direction).</p>
<p>I'm not 100% sure whether this is the correct explanation. Can someone else confirm?</p>
<p>another question.. parallel circuit always dissipates the most power??</p>
<p>Yeah that's right. For Simple Harmonic motion you have to remember this:</p>
<p>-----max +amplitude</p>
<p>-----origin</p>
<p>-----max -amplitude</p>
<p>if that's the bobbing mass, for exmaple. at the
Max -Amplitude [Velocity =0, acceleration = +max (going upwards)]
Origin [I remeber it being, Velocity = max, Acceleration = 0]
Max +Amplitude [velocity =0, acceleration = -max (going downwards)]</p>
<p>The origin's the tricky one. The velocity is max because it has just hit where it began, and is only continually moving becuase of Newton's First Law, anything in motion stays in motion unless acted upon by another force, and the Spring Force isn't great enough to pull it back until ilt reaches it's max negative amplitude, where velocity then becomes zero because, it's reversing directions.</p>
<p>get it?</p>
<p>just a tip to everyone.. i have been taking practice tests. make sure you remember all the formulas and their derivations. also the units for electricity. theres always one or 2 questions on which unit is which</p>
<p>thx guys. i understand it now... everything except electricity and magnetism.</p>
<p>I have a really tricky question that I've been working on for some time now and I can't remember how to do it...</p>
<p>The question is #6 here: <a href="http://www.collegeboard.com/prod_downloads/ap/students/physics/b_physics_b_frq_03.pdf%5B/url%5D">http://www.collegeboard.com/prod_downloads/ap/students/physics/b_physics_b_frq_03.pdf</a></p>
<p>It's a Fluids question, and I'm having trouble with part a-i and b-ii.</p>
<p>Thanks hugely in advance</p>
<p>have you downloaded scoring guidelines... they normally have the answers. i have yet to start on the free response questions.</p>
<p>There are no scoring guidelines for the 2003 or previous FRQ, only for 2004 regular and form B.</p>
<p>thats the main page right?
2003 is <a href="http://apcentral.collegeboard.com/repository/ap03_sg_physics_26598.pdf%5B/url%5D">http://apcentral.collegeboard.com/repository/ap03_sg_physics_26598.pdf</a></p>
<p>2003 b</p>
<p>anyone have 1984 practice test and willing to explain 59</p>
<p>crichessill, THANK YOU!!!!</p>
<p>Sooo.... Anyone else think they're pretty much screwed for tomorrow? :)</p>
<p>hey i just started studying :D</p>
<p>I hope they give easy part IIs and not some wierd ones that they haven't given but they expect us to know the topic for</p>
<p>hey how long is this test ? anyone?</p>
<p>3 hours..? Aren't they all 3 hours?</p>
<p>econ is 2 hrs and 10 mins i think? </p>
<p>calc bc is 3 and half hours </p>
<p>ap us history is 3 hours and 45 mins</p>
<p>US is really that long? I don't remember it beign almost 4 hours. But yeah, I'm pretty much screwed. But I needed a 5 to get credit, so I'm just hoping for a 3. I dread getting a 1 though, so I need a 2 at least.</p>
<p>Keep posting questions to review, people.</p>