[填空题]
A 70-cm-diameter wheel accelerates unr*x4r u/ir dsu+ 7qe/k b.m:mbifdztk*o wo2n4.ormly about its center from 130 rpm to 280 tw2. zno *o4dkrpm 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. $a_R$ $m/s^2$ $a_{tan}$ $m/s^2$