[填空题]
A cooling fan is turned off when it is running at 8ao.o0if( 0x.rvfn f tl2;qzn:50rev/min It turns 15os -eb/8e av4f*ukwga + o6uz000 revolutions before it comes to b-g/k8uvze0 o 6f s*eau4ao w+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