[填空题]
A 70-cm-diameter wheel accs,eq e c0tw)kju6u z+d61xf /celp,ku:qqx /z -a:p e/eznrr.u(rfl+e6 erates uniformly about its center from 130 rpm to 280 rpp u e:.u(a fznqp/e :6k/+rr,x-ezlqrm 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. $a_R$ $m/s^2$ $a_{tan}$ $m/s^2$