COUPLE – MOMENT OF A COUPLE
What is definition of Couple in engineering mechanics? Define moment of a couple?
The perpendicular distance (x) between the lines of action of two equal and opposite forces is known as arm of the couple. The magnitude of the couple (i.e. moment of a couple) is the product of one of the forces and the arm of the couple. Mathematically,
Moment of a couple = P x X
A little consideration will show, that a couple does not produce any translatory motion (i.e. motion in a straight line), but a couple produces a motion of rotation of the body on which it acts.