ping-pong projectile

This weekend I was at my friends house and playing a game of ping pong. Justin was my opponent and he beat me by a lot because he's a ping pong pro, but during the match i noticed that the ball traveled as a projectile. A projectile is an object that is traveling through the air with only gravity acting upon it. This means that when i hit the ball, it travels at a constant forward velocity but it's vertical velocity is constantly changing due to gravity. If i hit the ball with positive vertical velocity over the net, it travels upward but at a decreasing rate, due to the negative acceleration of gravity, until it reaches its peak and vertical velocity is zero. Its vertical velocity then decreases at an increases rate till the ball hits the other side of the table. All the while, its horizontal velocity remains constant. Luckily there was no wind in the garage to affect the projectile's path. Also, the wind resistance of the ping pong ball was not great enough to disrupt the projectile motion.

Soccer Ball Acceleration

This weekend i played a soccer game at waipio soccer park in the afternoon. Are team lost the game but in the process I realized that a soccer ball undergoes both positive and negative acceleration. As i kicked the ball during a goal kick it went from a velocity of zero to around 30 mph by the time it left my foot resulting in a very high acceleration. But, as soon as the ball left my foot at 30 mph it immediately began slowing down as it rolled across the grace. It traveled around 50 yards before coming to a complete stop. This decrease in velocity is an example of negative acceleration. To bad this physics epiphany did not help us win the game.