<p>Oh well. I guess I was wrong. Angular momentum is pretty easy to understand anyway =/</p>
<p>The whole idea of momentum is mass times velocity. You can carry analogous concepts between linear systems and rotating systems, and only reason why they differ is because what you are doing is really accounting for the linear momentum of every single infinitesimally-sized particle (well at the quantum level we get quantised momentum, but whatever!) which will be the same if the distance measured of the particle from the centre of rotation is constant even if the angle differs. Hence, the extra metre dimension, and why torque happens to have the same dimensions as linear energy. </p>
<p>So after this concept is noted, the whole idea of torque = RxF can be extracted from your middle school work with simple machines like levers. A longer lever results in more mechanical advantage, so the whole idea of torque = RxF = TR can be regrasped even if you forget. T=I*alpha is just the rotational version of F=ma.</p>
<p>Mass and moment of inertia both correspond to inertial concepts, while angular velocity and linear velocity are both the moving concepts.</p>
<p>As you get into things like capacitors and inductors, you can think of items as the “moving” term and others as the “inertial” term. so 0.5LI^2, 0.5CV^2, etc. </p>
<p>The other thing that helps a lot is a solid conception of calculus. </p>
<p>What I don’t get is simple harmonic motion and thing based off of it, like inductor-capacitor circuits. I’m not comfortable with how the syllabus treats it. It gives us a second order differential equation and automatically expects us to grasp the concept without proof that the solution to the differential equation is a trig function. I mean, it’s kind of hard to grasp if you don’t know how the math works, especially since it becomes harder to re-derive. Of course if you know trig you can use some common sense …</p>
<p>do we get calculator for physics C MC?</p>
<p>
</p>
<p>NO, you only get it for the FRQ’s, this applies to both the B and C tests. The same hold true for the formula sheet and table of values. :)</p>
<p>^ok. just checking :)</p>
<p>my prediction (well actually my hope) is that the frq has 2 newtonian mechanics an elctrostatics a ideal gas law, a random lab like always and prolly a modern physics q.</p>
<p>Hey guys, no time to write out mc answers this AM,
so the question I made up today is an FRQ…</p>
<p>A pendulum with length 1 m has a mass of 1 kg at
the end. The mass has +200 micro-C of charge. An
oppositely charged identical mass sits 10 m
directly below the lowest point of the arc of
the pendulum. What is the period of oscillation?</p>
<p>I am so mad that I got the Barrons AP Physics C review book. It has tons of unnecessary information, and because I haven’t taken calculus, I could barely understand any of the information. My friend has PR, and it looked so much better. I’m kind of freaking out a little now.</p>
<p>if you’re freaking out use the cram sheet. google it.</p>
<p>
</p>
<p>Intuitively speaking, 10 m is kind of far – I wouldn’t be surprised if the effect were negligible. </p>
<p>Hmm … T = 2pi * sqrt (l/g) </p>
<p>But the equivalent of g is variable because distance from the charge increases. </p>
<p>This isn’t a nice problem. </p>
<p>Am I missing something? I have to re-derive the period equation, don’t I?</p>
<p>Someone please explain to me the right hand rule or lead me to somewhere that does explain it easily.</p>
<p>please…</p>
<p>my teacher sucks at explaining it</p>
<p>hey can anyone explain 2005 free response form b question 3 part d to me?</p>
<p>For right hand rule:
<a href=“http://talk.collegeconfidential.com/ap-tests-preparation/504798-right-hand-rules-physics-b.html?highlight=right+hand+rule[/url]”>http://talk.collegeconfidential.com/ap-tests-preparation/504798-right-hand-rules-physics-b.html?highlight=right+hand+rule</a></p>
<p>I have a question. Could somebody explain this one to me?</p>
<p>Two objects having the same mass travel toward each other on a flat surface, each with a speed of 1 m/s relative to the surface. The objects collide head-on and are reported to rebound after the collision, each with a speed of 2 m/s relative to the surface. Which of the following assessments of this report is most accurate?
a) Momentum was not conserved, therefore the report is false [What I thought]
b) If potential energy was released to the objects during the collision, the report could be true
c) If the objects had different masses, the report could be true
d) If the surface was inclined the report could be true
e) If there was no friction between the objects and the surface, the report could be true</p>
<p>The right answer is B. Where would the potential energy come from and how would it be released? thanks.</p>
<p>Yeah I remember this question (it’s physics B but could be C question). Linear momentum is conserved as long as no outside force is acting on the system. Therefore, some outside force COULD be releasing potential energy, i.e. if a spring was attached to one of the objects.</p>
<p>
</p>
<p>Remember those examples about decaying nuclei? Or when an alpha particle hits a uranium nucleus and suddenly that nucleus emits more alpha particles … </p>
<p>Well, it’s not a perfect example because the rest mass changes (due to binding energy), but while momentum must be roughly conserved (I have no idea how to factor in conservation of momentum when some part of the mass changes into energy, but the change in mass is mostly negligible compared the energy released), potential energy has been converted to kinetic energy.</p>
<p>same…i have a huge eng research paper 2 do…due 2morrow and i dont even have athesis yet much less 10 pages</p>
<p>Nice Isabel, love the work habit -:D</p>
<p>Here’s a practice AP Physics C Question:</p>
<p>A yo-yo with string wrapped around it is a solid cylinder (I = 0.5MR^2), find the downward acceleration and tension in the string. The yo is being released straight up-and-down. Its all in the y-direction. Express all answers in terms of g (gravity)</p>
<p>Sorry if the wording is complex, but this a good problem, could be a potential frq :)</p>
<p>yeah…im soooo screwed ive been fiddling with the stupid thing 4 a month but its just like a brick wall…plus the fact that thers about no literary crticisms on plaths short stories for me 2 “interact with”
say would anyone want 2 take a physics break and read over it 4 me?</p>