Definition:Velocity

Definition
The velocity of a body $M$ is defined as the first derivative of the displacement of $M$ from a given point of reference with respect to time:


 * $\mathbf v = \dfrac {\mathrm d \mathbf s}{\mathrm d t}$

Colloquially, it is described as the rate of change of position.

It is important to note that as displacement is a vector quantity, then it follows from Derivative of Vector that so is velocity.

Dimension
Velocity has dimension $L T^{-1}$.

Units

 * The SI unit of velocity is the metre per second $\mathrm m \ \mathrm s^{-1}$, or, less formally, $\mathrm m / \mathrm s$.


 * The CGS unit of velocity is the centimetre per second $\mathrm {cm} \ \mathrm s^{-1}$, or, less formally, $\mathrm {cm} / \mathrm s$.

Thus:
 * $1 \ \mathrm m \ \mathrm s^{-1} = 10^2 \ \mathrm {cm} \ \mathrm s^{-1} = 100 \ \mathrm {cm} \ \mathrm s^{-1}$

Also see

 * Definition:Displacement
 * Definition:Position


 * Definition:Speed


 * Definition:Acceleration


 * Definition:Linear Momentum