This force names the dual Yang–Mills theory with strong coupling in Montonen-Olive duality. A gravitational analog of this force is often used to explain the frame-dragging caused by rotating objects. The components (15[1])of this force are the spacelike components of the Faraday tensor. What appears to be this force in the observer frame can be derived as a consequence of length contraction of a (*) charge density in a moving particle's rest frame, which is why this force is unified with a counterpart in special relativity. This force can do no work, since the direction of this force on a particle (10[1])is always perpendicular to its motion and equals (-5[1])“q v cross B.” For 10 points, moving charges give rise to what force that is combined with electricity in Maxwell’s equations? ■END■ (10[1])