What is the difference between moment and couple

I did not understand and did not find a reasonable translation! BTW in German engineers use "torque around". Add a comment.

Active Oldest Votes. Improve this answer. However, since you didn't apply the force directly in the center, you impart some spin on it If you applied a moment to a floating rod, it would start spinning because you didn't apply the force in its center, but also move off in some direction, because you applied an unbalanced force, and there was some net force in the direction you applied it.

McGarnagle 10 10 silver badges 20 20 bronze badges. Deependra subedi Deependra subedi 1. Kirankumar Kirankumar 1. Featured on Meta. Let us look at a system where a pair of forces, each with a magnitude , separated by a perpendicular distance form a couple. Since the net force must be 0, it follows that the forces must be acting in opposite directions and also that they have the same magnitudes. We calculate the torque due to these forces below. Let us consider the torque at.

This is the midpoint between the two forces. Each force contributes to a clockwise turning effect about this point. So, the total clockwise moment about O is:.

Hence the moment of the couple is a constant for any point on the plain of the couple. Whenever a force is applied to create a turning effect, in reality a torque is produced by a couple. For example, consider using a wrench to unscrew a bolt. When the force is applied to the end of the wrench arm, a force with the same magnitude is created at the bolt, which is the pivot in this case. These two equal and opposite forces create a couple, and the couple is generating the torque required to turn the bolt.

A couple consists of two equal and opposite forces acting with two different but parallel lines of action. Each force has its own moment. Let us think, what is the difference??? The value of moment of a couple will not be dependent over the location of point of interest. Moment of a couple will be a free vector.

While in case of moment of force, moment of a force will be dependent over the point of interest. Therefore, we have seen here the basics of moment of force, moment of couple and also the difference between these two with the help of this post. Do you have any suggestions? Please write in comment box and also drop your email id in the given mail box which is given at right hand side of page for further and continuous update from www.

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