[填空题]
A hammer thrower acceler )m pywy:,v3ixates the hammer from rest within four h-pkvd- 6 k l59yjy5lafull turns (revolutions) and releases it at a spel9 d-hyajk k-5p5vly6 ed 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} $