<p>I think moment of inertia was relevant SOMEWHERE on the test… XD</p>
<p>^Yes! </p>
<p>XDXDXD</p>
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<p>I honestly had no idea of what it was, and said something about what the moment of inertia would be if it weren’t rotating.</p>
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<p>Yeah, though I added a tenths and hundreths digit. And units.</p>
<p>deleted for reasons</p>
<p>^^I think it meant when the string or cord or whatever was massless (I=0).</p>
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<p>Part of the problem asked for us to set up a differential equation relating drag force with velocity, and then the next part asked us to solve the differential. Solving a differential usually necessitates an integral process, and that integral process may be worth a point or two. I had memorized the formula for drag force prior to the test, so I could have written the answer without any setup, but I still demonstrated the integral process, as I thought the test had asked.</p>
<p>You could use eigenvalues/eigenvectors or a Laplace transform. Neither of which would require integral calculus (maybe if you don’t memorize your Laplace tables), but both are definitely methods of solving diff.eqs</p>
<p>The thing is, none of those topics are covered in traditional high school calculus/math classes (AB/BC and their equivalents). For most high school students, solving the integral is actually the easiest option. But you’re right, it can be reasoned without actually setting up an integral on paper.</p>
<p>How did you guys do the last 2 parts of Question 1 Mechanics FRQ? I probably would have gotten the answer if I had a little more time.</p>
<p>^^^What on earth?</p>
<p>eigenvalues: assume an equation of the form ay’’ + by’ +cy = 0.</p>
<p>This can be solved as a<em>r^2 + b</em>r + c = 0.
Say a is 1, b is 1, c is -6.
r^2 +r-6 = 0. r=-3, or +2.
Therefore the solution to the diff.eq y’’ +y’-6y=0 is of the form y = c<em>e^-3t + C</em>e^2t. </p>
<p>If the solution above has a r that is complex, of the form p+qi, then
the diffeq has a solution of y = (e^pt)<em>(c</em>cosqt+C*sinqt), </p>
<p>etc. for higher order diff.eq.</p>
<p>shuuuuuutttttt uuuuuupppppp. you didn’t do that, so if you didn’t use calculus you got the freakin problem wrong.</p>
<p>if i were an ap grader i would not give credit to that because it is freaking obnoxious</p>
<p>The above is for a second-order differential. I used it because it best shows what an eigenvalue method is. </p>
<p>The differentials on the ap test only are first-order, or maybe second-order lacking the middle term. Those take less than 10 sec. to solve. And i did use that and it deserves credit.</p>
<p>they don’t mark it wrong if you (correctly) use calculus on the Physics B exam, so why would they mark this wrong? It’s right, and they can’t take off points.</p>
<p>Plus eigenvectors and eigenvalues are a mixture of differential calculus and linear algebra. And the type needed on the test was mostly differential calculus.</p>
<p>To be fair, I’m not sure what percentage of physics C graders remember enough linear algebra to properly judge your solution. They’ll have someone who can do it, and they’ll most likely have to end up giving your paper to them. It’s a bit of a hassle, but considering how much of a time crunch the mech FRQs were, if it saved you that much time, props to ya.</p>
<p>^^As long as you mentioned that you used that method, they should accept it. If you didn’t and you get two high-school Physics C teachers grading your FRQ, they look at it, say “What the f–k?” and give you no credit.</p>
<p>to be fair if each frq is worth fifteen pts, then each part worth 3 pts, they would at least have to give me one for the correct answer…</p>
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<p>Probably not. They’ll give more for the integration than, say, for the free-body diagram or for the centripetal force. (Mgcos(theta) look familiar?)</p>
<p>Ahhhh! I looked down after bubbling in my mech answers to see that… I ended up on 36!! </p>
<p>I know you can request to have your sheet hand scored. Does anyone know if they also take into account the circled answers in the booklet? Because I have all my answers circled in there.</p>
<p>Sent from my DROIDX using CC App</p>
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<p>As far as I know, CB burns/shreds/destroys the MC booklets once they scan them back into the system to make sure they got them back.</p>
<p>Ahhh I’m the stupidest person alive. I got maybe 1 point on question 2. Ahhhhh! Can I still get a 4 if I completely bomb a FRQ?</p>