[填空题]
A cooling fan is turned off when it is running at 850rev/min Ic f-byz0t t9 h(vwxf, om426rwt tutvl kp(rg;)v s2ye bxnqw. 848rns 1500 revolutions before it comes to a stpelvy8t4. (sx ; 2rkvb8 qgnw)op. (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