In softball, the pitcher throws underhand with the arm fully extended (straight at the elbow). In a fast pitch the ball,

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In softball, the pitcher throws underhand with the arm fully
extended (straight at the elbow). In a fast pitch the ball, of mass
m = 0.155 kg, leaves the hand at a speed of 139 km/h,
when the arm is pointed vertically downward.
Find the rotational kinetic energy, in joules, of the pitcher’s
arm-ball system, given that the arm's moment of inertia
is 0.71 kg⋅m2 and the ball leaves the
hand at a distance of 0.55 m from the
pivot.
What force, in newtons, do the muscles exert to cause the arm to
rotate, assuming the force is constant and its effective
perpendicular lever arm is 4.8 cm? Assume also that the
pitcher's arm starts extended horizontally behind her at rest and
the ball is released at the bottom of the swing, as described in
part (a). Approximate the arm as a uniform rod.