Velocity

Velocity, rate of linear motion of a body in a particular direction. Velocity is a vector—that is, it has both magnitude and direction. The magnitude of velocity, known as speed, is usually expressed in terms of distance covered per unit of time (usually the hour or second)—for example, kilometres per hour or feet per second. Velocity can be constant or accelerated. Velocity, uniform, or constant, can be determined simply by dividing the distance covered by the time taken to travel that distance. When an object is accelerated, the object's velocity vector changes in each unit of time. Acceleration can consist of a change in the direction of the velocity vector, or its magnitude, or both. See Mechanics.