Moment of Force:
It is the turning effect produced by a force, on the body, on which it acts. The moment of a force is equal to the product of the force and the perpendicular distance of the point, about which the moment is required and the line of action of the force.
M = P x l
P = Force acting on the body
l = Perpendicular distance between the point, about which the moment is required, and the line of action of the force.
Graphical Representation of Moment:
Consider a force P represented in magnitude and direction, by the line AB. Let O be a point, about which the moment of this force is required to be found out. Form O, draw OC perpendicular to AB. Join OA and OB.
Now, the moment of the force P about O
= P x OC = AB x OC
But AB x OC is equal to twice the area of triangle ABO.
Thus the moment of a force, about any point is equal to twice the area of the triangle whose base is the line to some scale representing the force and whose vertex is the point about which the moment is taken.
Types of Moment:
The moments are of the following two types:
1. Clockwise Moments
2. Anti-clockwise Moments