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A solid uniform disk of mass 19.0 kg and radius 70.0 cm (.7 m) is at rest FLAT on a frictionless surface. A string is wrapped around the rim of the disk and a constant force of 35.0 N is applied to the string. The string does not slip on the rim. The string is being pulled. When the disk has moved a distance of 6 m, what is the speed of the center of mass?
Relevant equations (I think...):
I=1/2MR^2
FR=Iα
α=a/R
So far, I have:
FR=Iα
FR=1/2MR^2(a/R)
F=1/2Ma
a=2*F/M=3.33333 m/s^2
and then,
v^2=2*a*6m, since initial velocity is 0.
v=7.26 m/s
But this is wrong, and I'm not sure why. Please help!
Relevant equations (I think...):
I=1/2MR^2
FR=Iα
α=a/R
So far, I have:
FR=Iα
FR=1/2MR^2(a/R)
F=1/2Ma
a=2*F/M=3.33333 m/s^2
and then,
v^2=2*a*6m, since initial velocity is 0.
v=7.26 m/s
But this is wrong, and I'm not sure why. Please help!