Linear velocity Velocity is the rate of change of the position of an object, equivalent to a specification of its speed and direction of motion.Velocity is an important concept in kinematics, the branch of classical mechanics which describes the motion of bodies.Velocity is a vector physical quantity; both magnitude and direction are required to define it. The scalar absolute value (magnitude) of velocity is called "speed", a quantity that is measured in metres per second (m/s or m·s?1) in the SI (metric) system. Mechanics QUDT http://qudt.org/vocab/quantity#Linearvelocity This has the same dimensionality as volumetric flux, but is expressed differently. ODM2 Units Type Controlled Vocabulary ODM2 Working Group A vocabulary for describing the type of the Unit or the more general quantity that the Unit represents.