My brother is having trouble solving this problem, its been awhile since I did this sort of problem and was wondering if anyone could help. Here's the problem:

A 1.5 kg ball and a 2.9 kg ball are connected by a 1.0 m long rigid, massless rod. The rod is rotating cw about its center of mass at 30 rpm. What torque will bring the balls to a halt in 5.0 s?

I think you need to find the moment of inertia and convert rpm into rad/s, but I can't remember it right.
Thanks!

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-Randy Wakefield

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