[填空题]
A cooling fan is tur0j*xjtv6dhl9qbuk; x a 23bs6-/ dec ined -y z+jrq h9-wge6qbiru1cw3;off when it is running at 850rev/min It turns 1500 revolutions before it comes ;wqi9gqj6 +ru zcr- ebhyw 13-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