An electron is a distance d from a dipole moving along the axis of the dipole, where d is much larger than the separation between the charges of the dipole. At this point, the magnitude of the force on the electron is 6e-8N. the electron moves a distance 3d from the dipole. What is the new magnitude of the force on the electron due to the dipole at this point?
--The answer is F= 2.2x10-9but I don't understand how to get this answer from the given information.