- #1
delecticious
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Homework Statement
M, a solid cylinder (M=2.07 kg, R=0.135 m) pivots on a thin, fixed, frictionless bearing. A string wrapped around the cylinder pulls downward with a force F which equals the weight of a 0.570 kg mass. Starting from rest, the mass now moves a distance 0.350 m in a time of 0.490 s. Find Icm of the new cylinder.
Homework Equations
T -torque
I - moment of inertia
s = 1/2(v0 +vf)t
T/alpha = I
transational acceleration (at) = (alpha)r
translational force (Ft) = m(at)
T = Ft(r)
The Attempt at a Solution
I started out by solving for accleration using the time, distance and initial velocity given, but it's from there where I'm completely confused. To find I, I have to divide T by alpha, but if T is equal to m(at)r which can also be rewiten as mr^2(alpha) then won't the alpha's cancel out making fiding the acceleration useless? When I do that I get mr^2 = I but that can't be right. Anyone know what I'm doing wrong?