I have a genral question. I just do not understand two concepts: 1. The idea of a couple being a free vector: If a couple produces a moment around the midpoint of the distance between the two forces that create a couple then how come if we move it to a different point of a body it creates the same effect. Wouldn't it rotate the body a round new point? 2. How can a couple and a force bew resolved in to a single resultant force. I have seen questions in a text books that have a bunch of forces and couples acting on a body and they ask for the resultant force without a couple. If the couple can be moved to any point and force can not than how come we can find the resultatn force wihtout a couple? As I understand, the moment of a force can not cancel a couple since it is fixed around a point and a couple is not? Thank you very much for al of you answers. I would really appreciate if someone could explain these two things for me.