Action-Reaction in Action

Bat Hitting the Ball – Increasing Momentum

My Backyard

Description:

This picture was taken in my backyard. This picture shows the impact force from the bat on the baseball. The ball’s momentum is zero until the baseball bat makes contact with it. Newton's third law of motion applies to this collision between the bat and the ball. In the collision between these two objects, both experience forces. These forces are equal and are in opposite directions. These forces cause the ball to speed up and makes the baseball bat to slow down. The forces are equal in magnitude and opposite in direction, the acceleration of the objects are not necessarily equal in magnitude.

Most observers have difficulty with this concept because they think the drastic change in speed is given to the ball because of the collision. However, they are not observing imbalanced forces between the ball and baseball bat, but different accelerations. Both baseball bat and ball experience equal forces, yet the ball experiences a greater acceleration due to its smaller mass. In this collision as in all collision, there is a force on both objects. This force causes an acceleration of both objects, but the less massive object, in my case the baseball, would receives the greatest acceleration.

In this collision, the baseball experiences a force for a very small amount of time. This force changes the momentum of the baseball, where the baseball's mass speeds up. The impulse experienced by the baseball equals the change in momentum. The impulse the baseball experiences increases its momentum. In order to increase the momentum of the ball off the tee the most, the hitter should follow through when hitting the ball off the tee. The follow through of the swing increases the time of collision, which contributes to an increase in the velocity of the ball.

An example from the real world would be a bat hitting a baseball. The bat and the baseball make contact for about two milliseconds. We know that the baseball tends to fly to the outfield at a much faster rate. So obviously, this contact revolves around the conservation of momentum occurs in this collision. This law says that there is the same amount of momentum before the collision as there is after the collision. So to see if this is true then you would add up the bat’s momentum and the ball’s momentum before the contact. Then you would have to check and see if that equaled the momentum of bat and the momentum of the ball after the contact. In this collision, the bat’s momentum is reduced and it is transferred to the momentum of the baseball. The bat and the ball, both experience an equal change in momentum though from the impact. However, since the mass of the bat is much greater, the change in momentum is much smaller for the bat than it is for the ball.

References:

“Science of Baseball”- http://www.exploratorium.edu/baseball/howfar.html

“The Physics Classroom” - http://www.physicsclassroom.com/Class/momentum/momtoc.html

To find out more about Momentum and Impulse check out these websites:

“Impulse and Momentum”- http://www.mathsrevision.net/alevel/mechanics/Impulse%20and%20Momentum.htm

“Momentum & Impulse PowerPoint Slideshow”- http://www.dboccio.com/Powerpoint/Momentum%20and%20Impulse_files/frame.htm#slide0001.htm

“Momentum & Impulse p = mv"- http://www.studyphysics.ca/30/momimp.pdf

“Science of Baseball”- http://www.exploratorium.edu/baseball/howfar.html

“The Physics Classroom” - http://www.physicsclassroom.com/Class/momentum/momtoc.html