A string wrapped around a cylinder, and is held by a hand (to the up right of the cylinder so the cylinder is rotating clockwise) that is accelerated upward so that the centre of mass of the cylinder does not move. a) Find the tension in the string. b) Find the angular acceleration of the cylinder. c) Find the acceleration of the hand.(adsbygoogle = window.adsbygoogle || []).push({});

a)The only force that exerts the a torque on the cylinder is the tension:

Segma torque = I *alpha

T*R = I * alpha

The hand force is: Sigma Fy=ma,y

Mg – T = ma,t (I am not sure if its minus or plus here)

at=R(alpha)

(mg-T)/m=R(TR/I)

so T = mg/(1+(mR^2/I) this is the tension of the string

b) how to get the angular acceleration here?

c) mg-(mg)/(1+(mR^2/I)) = m a,t

so a,t =(1/(1+I/mR^2)g this is the acceleration of the hand.

Is my reasoning correct?

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# Homework Help: Rotation Newton's second law

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