rotatory motion

(i) omega0 = 1200 rpm = 40 pi rad / s;

omega = 3120 rpm = 104 pi rad / s

using omega = omega0 + alpha x t

104 pi = 40 pi + alpha x 16

alpha = 66 pi / 16 = 33 pi / 8 rad / s²

(ii) theta = omega0 x t + (1/2) x alpha x t² 

theta = 40 pi x 16 + (1/2) x (33 pi / 8) x 16 x 16 = 640 pi + 528 pi = 1168 pi

So number of revolutions = 1168 pi / 2 pi = 584