As you catch a
fast-moving fastball, why is it wise to move yourhand in the
direction of the ball's motion? explain in terms ofwork and
energy.

Answer & Explanation:

A fast-moving ball always possesses kinetic energy and to stop it from moving, you have to do the same amount of work i.e. expend the same amount energy in the opposite direction to the ball.

During impact: The amount of work done in stopping the ball (force * distance) = the kinetic energy of the ball

If you hold your hand in a steady position the ball tend to hit and travel within a shorter distance thereby making you be in need of a greater force to stop the ball but if you move your hand in the same direction to the ball, the ball travel within a longer distance thereby reducing the force needed to stop the ball.