# What is the formula for Torque acting due to couple (or) Moment of couple ?

Posted in Scalars and Vectors | Email This Post |Two equal and opposite parallel forces acting at different points in a body constitute a couple. Pedals of bicycles is the example for couple, where the two forces are equal but acting in opposite direction.

**Torque acting due to couple (or) Moment of couple Torque** is calculated by the product of either of forces forming the couple and the arm of the couple.

Torque = one of the force × perpendicular distance between the forces.

In the figure, two equal forces F and F acting on the arm LM. Let us consider O as the mid-point of the arm .The forces F and F, which constitute a couple, are acting in opposite direction.

From the figure, the formula or equation for Principle of moments is given as,

**Moment of couple or torque = F × LM.**

The moment becomes zero when the forces acting on the body have the same line of action. When the forces are at right angles to the arm (θ=90^{0}), the torque is maximum.