[填空题]
A cooling fan is turned offj:gbqv izj1 m*q.q49u when itf(h 7n kx* 9eto+bmky/ is running at 850rev/min It turns 1500 revolutions before it comes to a sn9o +fbeh 7/mt*xkky (top. (a) What was the fan’s angular acceleration, assumed constant? $\frac{rad}{s^2}$ (b) How long did it take the fan to come to a complete stop? s