Definition:Moment of Couple

Definition

Let $C$ be a couple composed of the forces $\mathbf F_1$ and $\mathbf F_2$.

The moment of $C$ is a vector given by:

$\mathbf M = \mathbf F_1 \times \mathbf d$

where:

$\mathbf F_1$ is one of the forces that compose $C$

$d$ is the displacement from $\mathbf F_1$ to $\mathbf F_2$.

Hence:

the line of action of $\mathbf M$ is perpendicular to the plane containing $\mathbf F_1$ and $\mathbf F_2$

the magnitude of $\mathbf M$ is equal to $F d$.

Also see

• Results about moments of couples can be found here.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): couple
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): couple