Here's why:

* Velocity is a measure of how fast something is moving and in what direction.

* Acceleration describes how the velocity of an object changes over time.

For example:

* If a car speeds up, its velocity is increasing, and it's accelerating.

* If a car slows down, its velocity is decreasing, and it's decelerating (which is a type of acceleration).

* If a car turns a corner, its direction changes, even if its speed remains constant. This change in direction also means the velocity is changing, so the car is accelerating.