[填空题]
A cooling fan is tureqew)y-w 9g pur)n ).n yz-n-+ ybq64zem dp7tned off when it is running at 850rev/min It turns 1500 revolutip-7m6z+t 4- ynzd beyqons before it comes to a stop. (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