Engineering Mechanics
The law of the machine is (where P = Effort applied to lift the load, m = A constant which is equal to the slope of the line, W = Load lifted, and C = Another constant which represents the machine friction.)
If any number of forces acting at a point can be represented by the sides of a polygon taken in order, then the forces are in equilibrium
If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, then the forces are in equilibrium
If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium
If a polygon representing forces acting at a point is closed then forces are in equilibrium