# Moment of a force

The moment of a force (also known as torque) is a measure of the tendency of the force to rotate an object around a given axis. For instance a force acting on a lever causes a moment about the lever’s pivot point.

• A force $F$ acting along a line whose minimum distance from point $P$ is $d$ causes a moment $M=Fd$ about the point $P$.
• A force $\mathbf{F}$ acting at a point with position vector $\mathbf{r}$ has moment $\mathbf{\tau} = \mathbf{r} \times \mathbf{F}$ about the origin (where $\times$ denotes the vector or cross product).

Moment has dimensions $ML^{2}T^{-2}$ and SI unit Nm, Newton metres.