Which phrase describes velocity?

A. A synonym for speed

B. A vector quantity

C. A quantity with magnitude only

D. A quantity with no units

Velocity is a vector quantity. Speed is a scalar quantity. While the magnitude (number) of speed and velocity may be equal, what makes velocity a vector quantity is that it includes a direction. Speed is a scalar quantity because there is no direction associated with it.

The correct answer is B: A vector quantity.