[justify]This applet depicts the motion of a basketball as it travels through the air without taking into account the air resistance. We'll consider the motion of the ball [i]after[/i] it is projected and [i]before[/i] it lands. To put it another way, we're interested in how the ball moves when it's free to move through the air under the influence of gravity alone.[/justify]With that in mind, there are [b]two key facts to remember[/b]: [br][justify][/justify][list=1][*][justify]On the vertical axis, the acceleration is due to gravity, which is constantly pointing downward towards the center of the earth with a magnitude of 9.81 ms[sup]-2[/sup][/justify][sup][/sup][/*][*][justify]On the horizontal axis, there is no acceleration since air resistance is ignored. As a result, the velocity [b]v[/b][sub]x[/sub] in this direction remains constant and equals the initial velocity [b]u[/b][sub]x[/sub]. As a consequence of this, if the ball is launched from a pickup car and the car starts to move at this velocity [b]v[/b][sub]x [/sub]at the same time as the ball is released, the ball will land on the car again.[/justify][/*][/list][sup][/sup][list=1][/list][justify][/justify]