[填空题]
A 70-cm-diameter wheel accelerates u,n5s+ a,8emymghp( a mv d.xvz7v*p-rniformly apy f/k,z3fh6sw gi4b7bout its center from 130 rpm to 280 rpm in 4.0 f,3 ghz7 if4/p6sy kbws. 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. $a_R$ $m/s^2$ $a_{tan}$ $m/s^2$