* Velocity is a measure of both speed and direction.
* Acceleration is the rate of change of velocity.
If an object is moving at constant velocity, its speed and direction are not changing. Since there is no change in velocity, there is no acceleration.
Example: A car driving on a straight road at 60 mph is moving at constant velocity. As long as it maintains that speed and direction, it has no acceleration.
Important Note: It's possible for an object to have a constant speed but still be accelerating. This happens if the object is changing direction. For example, a car going around a circular track at a constant speed is still accelerating because its direction is constantly changing.
