Acceleration is defined as the rate of change of velocity per unit of time. If this rate of change of velocity remains uniform through out the motion of an object, it is termed as constant acceleration.

For example, if we consider the motion of a free falling object under gravity, the velocity of the object is uniformly increasing at the rate of 9.8 meters or 32ft per sec. until it falls on the surface of earth. This is a case of constant acceleration. It is termed as 9.8m /sec /sec , or 9.8 m/sec^2

******