[填空题]
A cooling fan is turned off when :cfpm q,mz r.(it is running at 850rev/m17e7r zqa gqs,tkr9g0 in It turns 1500 revolutions befoq7gea9sqr1 rzt7gk ,0re 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