Time Dilation Pictures of Planets and other Astronomical Objects Pictures of Crystals Pictures of Physicists Picture of ME Go back to Main Page. This is a movie of a vertical projectile. It illustrates the concept of the constant acceleration of gravity near the Earth's surface.
Velocity is the rate of position change.
It is the change in position divided by the time interval required for the change. The velocity of the projectile is represented by the blue arrow. The length of the arrow corresponds to the magnitude of the velocity and the direction of the arrow corresponds to the direction of the velocity. When the velocity changes, there is an acceleration. Acceleration is the rate of velocity change.