[填空题]
A cooling fan is turnedyk(7 x 0w1 6teivpdtf; off when it is running at 850rev/min It turn3l)k18l6wgt4icx w9p t8 m hbbs 1500 revolutions before it co x8 htll41 c9w83ibpmwbk)gt6mes 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