* Velocity is a vector quantity, meaning it has both magnitude (speed) and direction.

* Speed is just the magnitude of velocity.

Therefore, if speed changes, the magnitude of velocity changes, which means velocity itself changes.

Example:

* A car traveling at 60 mph east has a certain velocity.

* If the car speeds up to 70 mph east, its speed has increased.

* However, its direction remains the same (east).

* Since both speed and direction are components of velocity, the velocity has changed.

However, there's a catch:

* If only direction changes, velocity still changes, even if speed remains constant. For example, if a car turns a corner while maintaining a constant speed, its velocity changes because the direction of travel changes.

In conclusion:

* Any change in speed *always* results in a change in velocity.

* Any change in direction *also* results in a change in velocity, regardless of speed.