[填空题]
A cooling fan is turnedeb-y6i ejg)b )n1l5st off when it is running at 850rev s86e,2ui3f w vs5u njxvj36ka7:k r.a )mqbjv/min It turns 1500 revolutions before it comes jmru85vk u3s.6wq2a)fj7s :ex v kiv,anj 6b3to 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