Definition:Torque
Definition
Torque is a measure of strength of a force to effect rotation of a body.
Let $\mathbf F$ be a force acting at a point on a body $B$.
Let $B$ rotate around a point $O$ as a consequence of the action of $\mathbf F$.
Let $\mathbf r$ be the position vector of $P$ with respect to $O$, that is:
- $\mathbf r = \vec {OP}$
The torque about $O$ is defined as the cross product of the vector $\mathbf r$ and $\mathbf F$:
- $\bstau = \mathbf r \times \mathbf F$
Torque is a vector quantity.
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Symbol
- $\bstau$
The usual symbol used to denote torque is the boldface Greek letter $\bstau$ (tau).
Its $\LaTeX$ code is \bstau
.
Dimension
The dimension of measurement of torque is $\mathsf {M L}^2 \mathsf T^{-2}$.
This derives from its definition as:
- $\text{Force} \times \text {Displacement}$
Unit
The SI unit of measurement of torque is the newton-metre.
The CGS unit of measurement of torque is the dyne-centimetre.
The FPS unit of measurement of torque is the pound-foot.
Also known as
Torque is also known as the moment of a force, or just moment.
Also see
- Results about torque can be found here.
Sources
- 1989: Ephraim J. Borowski and Jonathan M. Borwein: Dictionary of Mathematics ... (previous) ... (next): torque
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): moment of a force (torque)
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): torque
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): moment of a force (torque)
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): torque
- 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): moment (in mechanics)
- 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): torque