[填空题]
A cooling fan is turned oelf6) x/.6zv sjhq+glff 39xfi6t fea6qw fx 10 6mp9tonwhen it is running at 850rev/min It turns 1500 revolutions before3qf1 90i6faw9ptx e of6nxt6m 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