What is the Difference Between Moment and Couple?

The main difference between a moment and a couple lies in the forces involved and the resultant force they produce. Here are the key differences:

• Moment: A moment is a measure of the turning effect of a force about a point. It is the product of the force and its perpendicular distance from the point of interest. A moment can be caused by a single force and may or may not accompany a resultant force.
• Couple: A couple is a system of two equal and opposite forces acting with separate lines of action. It is the result of the two forces creating their own moments, but the net moment of the couple is independent of the location of the point considered. A couple does not produce a resultant force.

In summary, a moment is a turning effect of a single force, while a couple is a system of equal and opposite forces that create a turning effect without a resultant force. A moment can occur with only one force, but a couple requires two forces to be produced.

Comparative Table: Moment vs Couple

The difference between a moment and a couple can be summarized in the following table:

In summary, a moment is produced by a single force and is the product of the force and the distance from its point of application. A couple, on the other hand, consists of two equal and opposite forces acting with two different but parallel lines of action. The net moment of the couple is due to the difference in the distance from the considered point and is independent of the location of the point considered.