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I have a problem dealing with torques and acceleration. I am sure I solved it right but when submitting the answers, I get the response "Incorrect"

The problem:

A wheel of radius 2 m, mass 53 kg, and moment of inertia (3/4) (53 kg) (2m)^2 about the center of mass is mounted on a frictionless horizontal axle.

(g = 9.8). A light cord wrapped around the wheel supports an object of mass 106 kg. The weight is released from rest at the level of A and falls a distance h, past level B (AB=28 m). a) Find the velocity as it passes B b) Determine the tension of the string.

I set up everything.

Torque = I* alpha = T*R since alpha = a/R and we know I, conclusion is T=42*a

Then: T=m(g - a): putting T from above, I got a=7.0189189 m/s^2

To find V as the mass passes point B: Vf^2 = 2*a*28m ---> and v at B = 19.83 m/s. This was OK

For b) I used T=m(g-a), since I know a = 7.0189189m/s^2 , I substituted it at the equation and I got T= 294.79 N but this is not the right answer.

Maybe I can use I*alpha = T*R and from that get T because everything is known, but I am not sure. Any suggestions?

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# Homework Help: Rotational Dynamics

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