[填空题]
An automobile engine slowsb 6ic5ma+z1vp8r1d jz down from 4500 rpm to 1200 rpm in 2.5 s. Calculate-t1vba qu /y*;:tof scn2)3gzrkmf2+xl w(o q (a) its angular acceleration, assumed constant, $rad/s^2$ (b) the total number of revolutions the engine makes in this time. $rev$