[填空题]
An automobile engineq2gwms* )z.hh slows down from 4500 rpm to 1200s3pfk6l q2t6.opr 5tp4 z mp9p rpm in 2.5 s. Calculate (a) its angular acceleration, assumed constant, $rad/s^2$ (b) the total number of revolutions the engine makes in this time. $rev$