What's the torque a baseball player exerts on the bat?

Question

A softball player swings a bat, accelerating it from rest to 2.7 rev/s in a time of 0.20 s. Approximate the bat as a 2.2 kg uniform rod of length 0.95 m, and compute the torque the player applies to one end of it.

Answer 1

angular acceleration = 2*(pi)2.7/0.2 = 84.8 rad/s^2

angle = 0.5 a*t^2 = 1.69646 rad

moment of inertia = (1/3)2.2(.95^2) = 0.66183

torque = (moment of inertia)*(angular acceleration) = 0.66183*84.8 = 56 N-m to 2 significant figures.