[填空题]
An automobile engine slows down from 4500 rpm to : : 48koskbwvv1200 rpm in 2. rezc23 0*4jf,d) u8r-qyipe+ prjqhv 5 s. Calculate (a) its angular acceleration, assumed constant, $rad/s^2$ (b) the total number of revolutions the engine makes in this time. $rev$