Question

what is acceleration

Answer 1

It is defined as rate of change of velocity. It is a vector quantity with SI unit m/s^2, represented by a.
a = v final - v initial/total time interval.

Answer 2

Here is your answer.

Acceleration :- the rate of change of velocity per unit of time.

The SIunit for acceleration is metre per second squared (m/s2). 

Hope it helps you.