[填空题]
A 70-cm-diameter wheel a cmmprkru)3 y,-8 z2vmccelerates uniformly about)4 11lr mc;disk na1zm its center from 130 rpm to 280 cs41iam1lmr )k1nd z ;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. $a_R$ $m/s^2$ $a_{tan}$ $m/s^2$