Category:Definitions/Internal Forces

This category contains definitions related to Internal Forces.
Related results can be found in Category:Internal Forces.

Let $B$ be a body.

An internal force is a force $\mathbf f$ exerted by one particle $P_1$ of $B$ on another particle $P_2$ of $B$, and to which there exists an equal and opposite reaction exerted by $P_2$ upon $P_1$.

Hence internal forces exist in pairs whose individual resultants are zero.

Hence the resultant of all the internal forces is also zero.