[填空题]
A 70-cm-diameter whe num6l4meeyy:qzn-35 d+pul(tmx kc ryk:)12 el accelerates uniformly about its center from 130 rpm to 280+ycx:m(pu)rkd2 tlk 1 rpm 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. $a_R$ $m/s^2$ $a_{tan}$ $m/s^2$