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.