Question

define acceleration explain its various type

Answer 1

When the velocity of an object changes IT is said to beaccelerating. Acceleration is the rate of change of velocity with time... This example illustrates acceleration as it's commonly understood, but acceleration in physics is much more than just increasing speed.
Hope it will help you my friend;)

Answer 2

 Acceleration is the rate of change of velocity of an object with respect to time. An object's acceleration is the net result of any and all forces acting on the object, as described by Newton's Second Law. 

Acceleration occurs anytime an object's speed increases or decreases, or it changes direction. Much like velocity, there are two kinds of acceleration: average and instantaneous.