An electric motor exerts a constant torque of τ=10N⋅m on a grindstone mounted on its shaft; the moment of inertia of the grindstone is I=2.0kg⋅m2. If the system starts from rest, the work done by the motor in 8.0 s was 1600 J, and the kinetic energy at the end of this time was 1600 J.  a) Suppose we now turn off the motor and apply a brake to bring the grindstone from its greatest angular speed of 50 rad/s to a stop. If the brake generates a constant torque of 30 N⋅m, find the total work done (including signs) needed to stop the grindstone. (J) B)Find the average power (including signs) needed to stop the grindstone in Part A. (W)

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An electric motor exerts a constant torque of τ=10N⋅m on a grindstone mounted on its shaft; the moment of inertia of the grindstone is I=2.0kg⋅m2. If the system starts from rest, the work done by the motor in 8.0 s was 1600 J, and the kinetic energy at the end of this time was 1600 J. 

a) Suppose we now turn off the motor and apply a brake to bring the grindstone from its greatest angular speed of 50 rad/s to a stop. If the brake generates a constant torque of 30 N⋅m, find the total work done (including signs) needed to stop the grindstone. (J)

B)Find the average power (including signs) needed to stop the grindstone in Part A. (W)

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