[填空题]
A hammer thrower acca jn.iques,go*li+60r,8kfqsukr ;r aitsuz 4 e;9r1o /ggus1(r+l:elerates the hammer from rest within four full turns (revolu ru g1;ris9/r1(e:ruz;4+ ksoaugslt tions) and releases it at a speed 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} $