[填空题]
A cooling fan is turned off when it is runnch jz+t6qc4 nw1lk +s-ing .kt0i2dcd+qwdg5 a+c6 cqzwwnv,j 3 2 at 850rev/min It turns 1500 revolutions before it comes to a s,6 .q0jq2d cwt iv2ww gczdc+a+5dk3ntop. (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