AP Physics C Problem

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1

<p>Ok, the question can be found here: </p>

<p>Fall</a> 2005 Physics 211 Hour Exam 3</p>

<p>Its question #4.
I just cannot get this question. Everytime I try to do it, I end up with the same wrong answer. I'll put the question here, but you kinda need the picture in the link to do the problem.</p>

<p>A solid cylinder of mass m = 1 kg, initially at rest, starts to roll down a rough surface inclined at a 30° angle to horizontal . The axis of the cylinder is attached through massless strings and pulleys to a square block of mass M = 2kg that rests initially on top of a horizontal table (see figure). What is the velocity of block M after the cylinder has traveled 1 m down the incline? The coefficient of kinetic friction between block M and the horizontal surface of the table is μ = 0.12. The cylinder rolls without slipping. </p>

<p>(a) 1.21 m/s
(b) 1.62 m/s
(c) 2.50 m/s
(d) 0.37 m/s
(e) 1.43 m/s</p>

<p>Thanks in advance for any help!</p>

2

<p>pahaha i haven’t done physics since last may but from what i see, i think an energy based approach would be best here. try using energy to solve it?</p>

<p>beginning = only potential energy?
end = rotational energy from cylinder + potential+ linear kinetic energy from both</p>

<p>and work is done by friction.</p>

<p>hahah sorry if what i said was rubbish…</p>

3

<p>Wow I’m an idiot…I kept forgetting to change the moment of Inertia of the cylinder from (1/2)MR^2 to (3/2)MR^2</p>

<p>Ok I finally got it but thanks anyways for the help though</p>