Resultant force with the help of moments:

How do you find the position of resultant force with the help of moments?

Sol.: At first find the magnitude and direction of the resultant force by the method of resolution. Now equate moment of resultant force with the algebraic sum of moments of given system of forces about any point or simply by using Varignon's theorem. This can also be found out by equating sum of clockwise moments and that of anticlockwise moments about the point through which resultant force will passes.

 Explain principle of moment:

Sol.: If there are number of coplanar non concurrent forces acted upon body, then for the equilibrium of the body, the algebraic sum of moment of all the forces about point lying in same plane is zero.

Which means that                 M = 0

Or we can say that,

Clock wise moment = Anticlockwise moment