where ''x'' is the position and ''v'' is the velocity. The velocity is a [[vector]], and its length or absolute value is called the ''speed''. The velocity has dimensions of length / time, and may thus be expressed in meter per second (in scientific usage). In daily life, miles per hour and kilometers per hour are more common units. | where ''x'' is the position and ''v'' is the velocity. The velocity is a [[vector]], and its length or absolute value is called the ''speed''. The velocity has dimensions of length / time, and may thus be expressed in meter per second (in scientific usage). In daily life, miles per hour and kilometers per hour are more common units. |