Anything that is caused to move in a direction brought about by gravitational acceleration and air resistance and record an initial velocity is a projectile. The direction taken by this projectile is known as trajectory. So, the acceleration of a projectile motion in a rectangular coordinate is represented by a sub x = 0 and a sub y = -g, where x represents the horizontal axis in a short range trajectory. Direction of movement along the axis is not brought about by gravitational acceleration. Movement is not pro or against gravitational pull. On the other hand, a sub y on the vertical axis or the y axis has acceleration because of the gravitational pull. Therefore, a sub y is equal to a value, minus gravitational pull.
