Velocity of an object is defined as the speed of an object moving in a definite direction. Velocity of an object can be uniform or variable. During uniform motion, velocity remains constant with time and change in velocity for any time interval is zero.Constant velocity is the velocity whose direction as well as magnitude remains constant. Uniform velocity is the velocity whose magnitude(only) increases with equal intervals of time.
The rate of change in the velocity of an object per unit time is referred as acceleration. Acceleration is zero for both uniform and constant velocity