[填空题]
A 70-cm-diameter wheel acceleratest87j pw-ua)ihx t 9fcue,23x p uniformly:guj; rulxf:a:. z hx/k2 ((sotbi1vj about its center from 130 rpm to 280 rpm ::;hxs2 brga: x k .fi jolu(t/(zju1vin 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. $a_R$ $m/s^2$ $a_{tan}$ $m/s^2$