[填空题]
An automobile engine slows z yrl;.eozrf-z4-tamlm4* *a down from 4500 rpm to 1200 rpm in 2.5 soiys8a nayn38tfps- 4v 0a(5h. Calculate
(a) its angular acceleration, assumed constant, $rad/s^2$
(b) the total number of revolutions the engine makes in this time. $rev$
