the difference between speed and velocity involves
Speed is a scalar quantity. i.e., it has only magnitude but no direction. Velocity, on the other hand, is a vector quantity and it has both magnitude and direction. It obeys laws of vector addition but does not obey laws of algebra.
(The symbol v is used for speed because of the association between speed and velocity, which will be discussed shortly.) 1  Speed is directly proportional to distance when time is constant: v â s (t constant)  Speed is inversely proportional to time when distance is constant: v â ât (s constant)