Acceleration

Introduction.
 If the velocity of an object changes.it is said to be moving with an acceleration.
 The time rate of change of velocity of a body is called acceleration.
As velocity is a vector so any change in velocity may be due to change in its magnitude or a change in its direction or both.i have given in mathematically shape of acceleration.

      

consider a body whose velocity v at any instant t changes to v. in further small time interval difference of t.the two velocity vector v and v. and the change in velocity, v.-v = change of v, are represented in picture above.