Editing Resultant force (section)

==Bound vector==
A force applied to a body has a point of application.  The effect of the force is different for different points of application.  For this reason a force is called a ''[[bound vector]]'', which means that it is bound to its point of application.

Forces applied at the same point can be added together to obtain the same effect on the body.  However, forces with different points of application cannot be added together and maintain the same effect on the body.

It is a simple matter to change the point of application of a force by introducing equal and opposite forces at two different points of application that produce a pure torque on the body.  In this way, all of the forces acting on a body can be moved to the same point of application with associated torques.

A system of forces on a rigid body is combined by moving the forces to the same point of application and computing the associated torques.  The sum of these forces and torques yields the resultant force-torque.