[填空题]
A cooling fan is turned off when i qccewt14nikk2o5e 4. y1t; akt is running at 850rev/min It turns 15r j zzl0 7kd0.s-1f (b5ffywiu00 revolutions before it comes to 0uy- rsk1jzb0(7i5fd.lwf fz 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