When is a system in equilibrium?

A system is in equilibrium when there is no resultant force and no resultant torque (or moment). A moment is the turning effect of applying a force on a body. It is the product of the force and the perpendicular distance from the line of action of the force to the pivot or point where the object will turn. We will only work in 2D and there are couple of ways you can check for equilibrium: 1) Calculation                                                                        2) Graphical method