[填空题]
A hammer thrower accelerates h-ztieoqno 8 n,nyk, *vl ;.;ithbh ;ec3 tcjv)t/;toit sj0 5fo,, kf4ae hammer from rest within four full turns (revolutions) and releases it at a speedek tj o, ci5/;fjt)ttf0bav;oh34 c s, of 28 $m/s$ Assuming a uniform rate of increase in angular velocity and a horizontal circular path of radius 1.20 m, calculate (a) the angular acceleration, $rad/s^2$ (b) the (linear) tangential acceleration, $m/s^2$ (c) the centripetal acceleration just before release, $m/s^2$ (d) the net force being exerted on the hammer by the athlete just before release, N (e) the angle of this force with respect to the radius of the circular motion. $^{\circ} $