[填空题]
An automobile engine slows down from 4500 rpm to 1200 rmm: nrixq*esh/z8 l: vv91o/e pm in 2.5 s. C:w5ilvsps 5qq :i7/i dwd6v2halculate (a) its angular acceleration, assumed constant, $rad/s^2$ (b) the total number of revolutions the engine makes in this time. $rev$