A body rotating at 20 rad/s is acted upon by a constant torque providing it a deceleration of 2 rad/s 2 . At what time will the body have kinetic energy same as the initial value if the torque continues to act ?

A body rotating at 20 rad/s is acted upon by a constant torque providi

1.	A body rotating at 20 rad/s is acted upon by a constant torque providing it a deceleration of 2 rad/s 2 . At what time will the body have kinetic energy same as the initial value if the torque continues to act ?
Answer» Initial angular velocity = 20 rad/s Therefore α = 2 rad/s² t₁ = ω/α ₁ = 20/2 = 10 sec Therefore 10 sec it will come to rest. Since the same torque continues to act on the body it will produce same angular acceleration and since the initial kinetic energy = the kinetic energy at an instant. So initial angular velocity = angular velocity at that instant Therefore time require to come to that angular velocity, t₂ = ω₂/α ₂ = 20/2 = 10 sec therefore time required = t₁ + t₂ = 20 sec.

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A body rotating at 20 rad/s is acted upon by a constant torque providing it a deceleration of 2 rad/s 2 . At what time will the body have kinetic energy same as the initial value if the torque continues to act ?

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