[填空题]
A cooling fan is turned off when it is runnzre.(:yy e jox g1 h q*jekcdwe:6030ning at 850rz u 4r66uzlry:;gt0njev/min It turns 1500 revolutions before it comes to a stop4nuz zlu ;t6jry r0:g6. (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