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1. The problem statement, all variables and given/known data

A rotating uniform cylindrical platform of mass 230 kg and radius 5.6 m slows down from 3.8 rev/s to rest in 16 s when the driving motor is disconnected. Estimate the power output of the motor (\rm hp) required to maintain a steady speed of 3.8 rev/s

2. Relevant equations

Wfriction=change in KE = -.5*I*w^2

power=work/time

3. The attempt at a solution

So I was was able to get the amount of work that the friction force does and it was -.5 (.5 * MR^2)w^2 = 45053.39J and that work done by friction is the same amount of work needed for the motor to output. So the power of the motor needed is 45053.39/16s = 2690.8Watts and to convert that to HP I just divide by 746W and got 3.6HP. is that right?

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# Homework Help: Power and torque what did i do wrong?

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