[填空题]
A 70-cm-diameter wheel accelerates uniyvkw s6ch31ym3 2;o eqforvs6vd)l u t :2 cu:f9vfjjgk*1mly about its center from 130 rpm to 280 r*6c1):u2jt:kfu sf v dvvgl j9pm 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. $a_R$ $m/s^2$ $a_{tan}$ $m/s^2$