[填空题]
A cooling fan is turned off when it is runtbbu,v,drtnwx xy*q hxo ;c 8tch(a +)l62l10 b*ye -wod12v lning at 850rev/min It turns 1500 revollwby-2v *do1eutions 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