[填空题]
A 70-cm-diameter wheehkncn8 g pcuy-cj+p */lg82l/l accelera:ske05frz9mgr h 6dwm4( (pfc39 qnmqtes uniformly about its center from 130 rpm to 280 n 9 3p c0f 6medm(rq qrmwz5h(4gs:fk9rpm in 4.0 s. Determine (a) its angular acceleration,$\approx$ $rad/s^2$(Round to one decimal places) (b) the radial and tangential components of the linear acceleration of a point on the edge of the wheel 2.0 s after it has started accelerating. $a_R$ $m/s^2$ $a_{tan}$ $m/s^2$