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Right after the Ping-Pong ball hits the table, it undergoes projectile motion. At the instant when Ping-Pong ball bounces off the table, it has an initial velocity with an upward angle. If we consider the initial velocity as a resultant vector, by separating it, we can get its horizontal and vertical components of velocity. Since the air resistance is so small that it can be negligible, during the entire motion, acceleration due to gravity, which is on the vertical plane and equals -9.80 m/s2, is the only acceleration to the entire system. Because there is no acceleration on the horizontal plane, the horizontal velocity of the Ping-Pong ball stays constant. Initially, acceleration due to gravity causes the Ping-Pong ball’s vertical velocity to decrease and gradually reaches zero, where the Ping-Pong ball is at the peak of the entire projectile motion. Then, acceleration due to gravity continues to cause the Ping-Pong ball’s vertical velocity to increase downward. Ultimately, when the Ping-Pong ball hits the table again, considering air resistance negligible, the initial velocity and the final velocity are the same in magnitude but different in direction.
Projectile Motion