Question:What is the difference between speed and velocity?
Speed is a scalar quantity – it only has a magnitude.
Velocity is a vector quantity – it must have a direction as well as a magnitude.
Both velocity and speed use the same units – metres per second (m/s).
Examples: speed = 5 m/s. velocity = 5 m/s to the south.
Sometimes we only care how fast an object is moving, so we can use speed.
But more often, knowing the speed does not help us unless we also know what direction the object is moving towards. So we use velocity instead.