Engineering Mechanics
Three forces acting on a rigid body are represented in magnitude, direction and line of action by the three sides of a triangle taken in order. The forces are equivalent to a couple whose moment is equal to
Is equal to twice the area of the triangle, whose base is the line representing the force and whose vertex is the point, about which the moment is taken
Is equal to the product of force acting on the body and the perpendicular distance of a point and the line of action of the force
Is the turning effect produced by a force, on the body, on which it acts