[填空题]
Pilots can be tested for the stresses of flying hi4 axn3+ip )fnug-shx+a4;nb ol - s5xkzhspeed jets in a whirling “human centrifug-a+ohss l4-xnkxz5;b e,” which takes 1.0 min to turn through 20 complete revolutions before reaching its final speed. (a) What was its angular acceleration (assumed constant), $rev/min^2$ (b) what was its final angular speed in rpm? $rpm$