Rotational kinetic energy:
where I is the moment of inertia and ω is the angular velocity.
Moment of inertial of a point mass:
Relationship between linear velocity and angular velocity.
In softball, the pitcher throws with the arm fully extended (straight at the elbow). In a fast pitch the ball leaves the hand with a speed of 139 km/h.
Find the rotational kinetic energy of the pitcher's arm given its moment of inertia is 0.720 kg⋅m2 and the ball leaves the hand at a distance of 0.600 m from the pivot at the shoulder (the ball is 0.156 kg).
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