[填空题]
A cooling fan is turned off when it is running 4 n q,co*yvbg(vab. *zsi+ -;giqako(at 850rev/min It turns 15d6i1: hm6 8;y3kvtr2dm itf ep6:oxxk00 revolutions before it comes tor 1ikye om38xh;fdt6 t i:pm 6dv:x62k 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