Q: The angular acceleration of a fly wheel is given by α = 12 – t, where α is in rad s^{-2} and t in second. If the angular velocity of the wheel is 60 rad s^{-1} at the end of 4 s, the angular velocity at the end of 6 s and the number of revolutions that take place in these 6 s, respectively are

(a) 54 rads^{-1}, 37.8

(b) 84 rads^{-1}, 57.8

(c) 74 rads^{-1}, 47.8

(d) 80 rads^{-1}, 50

Ans: (c)