**Rate of change of velocity**

Tanusri Gururaj, Academic content writer of Physics at Edumarz

The rate of change of velocity of a body with time is known as acceleration. It is a vector quantity just like displacement and velocity.

Acceleration = Change in velocity of object/Time taken

SI unit of acceleration is m/s2

Acceleration has a positive sign if it is in the direction of velocity and has a negative sign if it is in the opposite direction of velocity.

For an object in uniform motion on a straight line, the change in velocity is zero and hence, acceleration is also zero.

Uniform acceleration:

When the velocity of a body travelling on a straight line increases or decreases by equal amounts in equal time periods.

For example, a ball rolling down an incline.

Non-uniform acceleration:

When the velocity of an object changes at a non-uniform rate.

For example, a truck travelling on a straight road increases its speed by unequal amounts in equal time periods.

Instantaneous acceleration:

The acceleration of a body at a particular instant is known as instantaneous acceleration.