An electric dipole consists of two point charges (±q), each of mass m, fixed to the ends of a (mass less) rod of length d. (Do not assume d is small.)

(a) Find the net self-force on the dipole when it undergoes hyperbolic motion (Eq. 12.62) along a line perpendicular to its axis.

(b) Notice that this self-force is constant (t drops out), and points in the direction of motion–just right to produce hyperbolic motion. Thus it is possible for the dipole to undergo self–sustaining accelerated motion with no external force at all! 18 [Where do you suppose the energy comes from?] Determine the self-sustaining force, F, in terms of m, q, and d.