  The classical electromagnetic self-force on an arbitrary time-dependent
electric or magnetic dipole moving with constant velocity in vacuum, and in a
medium, is considered. Of course, in vacuum there is no net force on such a
particle. Rather, because of loss of mass by the particle due to radiation, the
self-force precisely cancels this inertial effect, and thus the spectral
distribution of the energy radiated by dipole radiation is deduced without any
consideration of radiation fields or of radiation reaction, in both the
nonrelativistic and relativistic regimes. If the particle is moving in a
homogeneous medium faster than the speed of light in the medium,
Vavilov-\v{C}erenkov radiation results. This is derived for the different
polarization states, in agreement with the earlier results of Frank. The
friction experienced by a point (time-independent) dipole moving parallel to an
imperfectly conducting surface is examined. Finally, the quantum/thermal
Einstein-Hopf effect is rederived. We obtain a closed form for the spectral
distribution of the force, and demonstrate that, even if the atom and the
blackbody background have independent temperatures, the force is indeed a drag
in the case that the imaginary part of the polarizability is proportional to a
power of the frequency.
