A pitcher throws a ball by rotating his arm around his shoul

A pitcher throws a ball by rotating his arm around his shoulder joint. If the ball is 0.05 kg and his arm is 5kg and 0.8 m long, what torque is required of the shoulder to accelerate the arm at 25 rad/s^2? Assume the arm is a solid stick and the ball is a point mass.

Solution

Torque = Moment of inertia x angular accelaration

=(1/3 * ML² + mL²⁾ x 25 rad /sec2

   M = Mass of shoulder + ball = 5.00

   m= mass of ball = 0.05 kg

L = 0.8 m

Torque = 26.9 33 N.m