m1 is at the origin pointing in the x-direction. This frame is called Local coordinates and is shown in the Figure on the right. The force of one magnetic dipole on another is determined by using the magnetic field of the first dipole given above and determining the force due to the magnetic field on the second dipole using the force equation given above. Using vector notation, the force of a magnetic dipole m1 on the magnetic dipole m2 is: where r is the distance-vector from dipole moment m1 to dipole moment m2, with . The force acting on m1 is in opposite direction. As an example the magnetic force for two magnets pointing in the z-direction and aligned on the z-axis and separated by the distance z is: , z-direction. The final formulas are shown next. They are expressed in the global coordinate system, Notes References See also Magnetic motor Magnetism