Which part of an object's rate of change best defines acceleration?

velocity

force

speed

position

velocity ...

The rate of velocity of an object is used to define acceleration at its best terms

Explanation:

Acceleration is the rate of change of velocity of an object. Velocity is different from speed because velocity is a vector quantity. Acceleration occurs due to change in position as the time varies from its original position.

Rate of change of position and force doesn't have predominant effect on acceleration. Therefore velocity is the most suitable to define acceleration.