This applet illustrates a couple. A couple is two forces applied a distance apart. One force is the negative of the other force. [br][br]In this applet you can control the application points for the two forces (A and B) and the force vector is controlled by the triangular point F.[br][br]Three calculations can be shown of the net moment of the two forces.[br]"About B" shows the calculation of the moment about point B where the moment due to the negative force is zero.[br]"Perpendicular Distance" shows the perpendicular distance times the magnitude of the force vector. Whether the moment is positive or negative can be determined from the right hand rule.[br]"Other Point" adds a point C where the sum of the two moments can be calculated about.[br]Observe how the moment changes as you move point C.