Imagine throwing a ball to someone. As the ball travels horizontally through the air, it also travels vertically because of the effects of the force of gravity. Any object moving in this way is called a projectile – an object moving under the influence of gravity.
The force of gravity produces the same downward acceleration on all objects.
Any mass (a mass or a ) will accelerate downwards at .
Some projectiles only move vertically. Other projectiles move horizontally and vertically at the same time. When we investigate the motion of a projectile, the horizontal and vertical motion of the projectile are kept separate.