Definition:Velocity
Definition
The velocity $\mathbf v$ of a body $M$ is defined as the first derivative of the displacement $\mathbf s$ of $M$ from a given point of reference with respect to time $t$:
- $\mathbf v = \dfrac {\d \mathbf s} {\d t}$
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 by definition of derivative of a vector that so is velocity.
Dimension
The dimension of measurement of velocity is $\mathsf {L T}^{-1}$.
Units
SI
The SI unit of velocity is the metre per second $\mathrm m \ \mathrm s^{-1}$, or, less formally, $\mathrm m / \mathrm s$.
CGS
The CGS unit of velocity is the centimetre per second $\mathrm {cm} \ \mathrm s^{-1}$, or, less formally, $\mathrm {cm} / \mathrm s$.
FPS
The FPS unit of velocity is the foot per second $\mathrm f \ \mathrm s^{-1}$, or, less formally, $\mathrm f / \mathrm s$.
Also see
Historical Note
The first person to treat the velocity as a vector was Leonhard Paul Euler.
Sources
- 1921: C.E. Weatherburn: Elementary Vector Analysis ... (previous) ... (next): Chapter $\text I$. Addition and Subtraction of Vectors. Centroids: Definitions: $1$. Scalar and vector quantities
- 1937: Eric Temple Bell: Men of Mathematics ... (previous) ... (next): Chapter $\text{VI}$: On the Seashore
- 1951: B. Hague: An Introduction to Vector Analysis (5th ed.) ... (previous) ... (next): Chapter $\text I$: Definitions. Elements of Vector Algebra: $1$. Scalar and Vector Quantities
- 1953: L. Harwood Clarke: A Note Book in Pure Mathematics ... (next): $\text {II}$. Calculus: Differentiation: Velocity and Acceleration
- 1965: Seth Warner: Modern Algebra ... (previous) ... (next): Chapter $\text {V}$: Vector Spaces: $\S 26$. Vector Spaces and Modules
- 1966: Isaac Asimov: Understanding Physics ... (previous) ... (next): $\text {I}$: Motion, Sound and Heat: Chapter $2$: Falling Bodies: Acceleration
- 1966: Isaac Asimov: Understanding Physics ... (previous) ... (next): $\text {I}$: Motion, Sound and Heat: Chapter $3$: The Laws of Motion: Forces and Vectors
- 1968: Murray R. Spiegel: Mathematical Handbook of Formulas and Tables ... (previous) ... (next): $\S 22$: Vectors and Scalars
- 1970: George Arfken: Mathematical Methods for Physicists (2nd ed.) ... (previous) ... (next): Chapter $1$ Vector Analysis $1.1$ Definitions, Elementary Approach
- 1992: Frederick W. Byron, Jr. and Robert W. Fuller: Mathematics of Classical and Quantum Physics ... (previous) ... (next): Volume One: Chapter $1$ Vectors in Classical Physics: $1.1$ Geometric and Algebraic Definitions of a Vector
- 2008: Ian Stewart: Taming the Infinite ... (previous) ... (next): Chapter $8$: The System of the World: Newton
- 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): rate of change