Question

What is a moment in Physics?

Answer 1

1. The moment of force is a tendency to rotate a body around an axis or a point.
2. A moment due to force doesn't have an equal and opposite force directly along its line of action.
3. The magnitude of the moment of a force acting about a point or axis is directly proportional to the distance of the force from the point or axis.
4. The moment of force can be defined as
   $$\begin{gathered} \mathrm{Moment}\mathrm{of}\mathrm{force}=\mathrm{Force}\times \mathrm{distance}\mathrm{between}\mathrm{the}\mathrm{force}\mathrm{and}\mathrm{axis}\mathrm{of}\mathrm{rotation} \\ \mathrm{M}=\stackrel{\rightharpoonup }{\mathrm{F}.\mathrm{d}} \\ M=F.d\cos \theta \end{gathered}$$
5. The SI unit of the moment is $\mathrm{Newton}.\mathrm{meter}\left(\mathrm{N}.\mathrm{m}\right)$
6. It is a vector quantity.
7. The center of the moment is the actual point at which force causes rotation of the body.
8. In the diagram, $\mathrm{r}$ is the axis of rotation.