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Rotation Problem

  • Thread starter timtng
  • Start date
25
0
A disk witht the radius R is launched with the angular velocity ω on a horizontal surface. How long will it take until the disk stops, if the coefficient of friction is μ.

This is what I came up with, but don't know if I did it correctly:

For frictional force I got μMg
-net torque = I(alpha), alpha = -μMg/.5MR = -2μg/R
ω = ω0 +alpha(t) >> 0 = ω-(2μg/R)t

I got t = (ωR)/(2μg) >>Is this the correct answer?

Thanks
 
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