118. A body rotating at 20 rad/sec is acted upon by a constant torque providing it a deceleration of 2 rad/sec

A body rotating at 20 rad/sec is acted upon by a constant torque providing it a deceleration of 2 rad/sec². At what time will the body have kinetic energy same as the initial value if the torque continues to act

(a)  20 secs

(b)  40 secs

(c)   5 secs

(d)  10 secs

Ans. a