Question

1.) We are going to play baseball. But, to make sure there aren’t any extra forces in the way, we will be playing in space (so there isn’t gravity, and there isn’t air resistance). When we play, we will separate the pitch of the ball and what happens after into four segments:

1. The ball is in the pitcher’s hand, and being thrown from rest until it leaves the pitcher’s hand

2.The ball is on the way from the pitcher to the bat

3. The ball is being hit by the bat

4. The ball has left the bat and is flying away after being hit

Fill in the table below with a “Yes” or “No” in each cell, to tell if you think there is a force and/or an acceleration in each of the segments.

	Force	Acceleration
Segment 1
Segment 2
Segment 3
Segment 4

Answer 1

1] While the ball is being released from the pitcher's hands, it is getting acceleration. Since the ball has a finite mass, due to Newton's 2nd law of motion, this acceleration will give rise to a force on the ball.

So, Yes and Yes for both force and acceleration.

2] While the ball is travelling to the striker, it travels with a constant velocity since there is no external force driving its motion anymore. Therefore, No and No for both force and acceleration.

3] While the ball is being hit, the momentum of the ball is changed by the bat in a small time [change in momentum is a result of change in velocity of the ball]. This gives rise to a force [F = dp/dt] and thus an acceleration.

So, Yes and Yes for both.

4] The ball now is under the action of no driving force and so it shall not acceleration by itself. Therefore, No and No for force and acceleration.