[填空题]
A cooling fan is turned off when it is running at 850rev/min It turns 1500 f2dl(sd c26dh rruk nh+9x2t j-evolution r+k -tjnux9h2s 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