[填空题]
A cooling fan is turned ofwm,lre/ a* 0tp2;jv dff when it is running at 850rev;j l vnq+ -if dbei87f9d5dt)v/min It turns 1500 revolutions before it comes tnf7f di 5;)bedv- dl+vq9ti j8o 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