* Velocity is a measure of both speed and direction. A body at rest has zero velocity.

* Acceleration is the rate of change of velocity. This means that acceleration can occur even if the body is initially at rest.

Example:

Imagine a ball sitting on a table. It has zero velocity (not moving). If you give the ball a push, it starts to move. This means it has gained velocity. The change in velocity from zero to some non-zero value is what we call acceleration.

Key Point: Acceleration is about *change* in velocity, not the velocity itself. A body can be accelerating even if it's momentarily at rest.

Other Examples:

* A ball thrown straight up in the air momentarily stops at its highest point (zero velocity) but is still accelerating due to gravity.

* A car at a red light has zero velocity but will accelerate once the light turns green.