Chapter 7, Problem 5A

Consider hitting a baseball with a bat. If we call the force the bat exerts against the ball the action force, identify the reaction force.

To determine

The reaction force in hitting a baseball with bat.

Answer to Problem 5A

The force exerted by the ball on the bat.

Explanation of Solution

Introduction:

According to Newton’s third law of motion, if the collision occurs between two bodies, both the bodies exerts force on one another. The magnitude of these forces are equal but they are acting in reverse direction. This third law of motion is also called by the name law of action and reaction.

When the bat hits the ball, both the bat and the baseball experiences the force. The force exerted by the bat on the ball and that exerted by the baseball on the bat are equal in magnitude and are acting in reverse direction. If the force exerted by the bat on the ball is the action force, then the force exerted by the ball on the bat is the reaction force. Due to this force, the speed of the ball goes up and that of the bat goes down. Even though the magnitude of action and reaction forces are equal, the magnitude of acceleration of the bat and the ball may not be equal. The acceleration of less massive ball would be greater than that of more massive bat.