Velocity

Velocity is speed in a given direction. It tells us both how fast an object is moving and the direction in which it is moving.

For example, an object travelling at $$5\ \text{m/s}$$ east has a different velocity from one travelling at $$5\ \text{m/s}$$ west. Their speeds are the same, but their directions are different.

An object's velocity therefore changes if its speed changes, its direction changes, or both change.