Question

Why does the velocity change when the boy hits the ball

Answer 1

Acceleration from gravity is always constant and downward, but the direction and magnitude of velocity change. At the highest point in its trajectory, the ball has zero velocity, and the magnitude of velocity increases again as the ball falls back toward the earth

Step-by-step explanation:

Answer 2

Freefall is a special case of motion with constant acceleration because acceleration due to gravity is always constant and downward. This is true even when an object is thrown upward or has zero velocity.

When a ball is thrown up in the air, its velocity is initially upward. Since gravity pulls the object toward the earth with a constant acceleration g, the magnitude of velocity decreases as the ball approaches maximum height. At the highest point in its route, the ball has zero velocity, and the magnitude of velocity increases again as the ball falls back toward the earth.