| Within the realm of classical physics and in a world that
| does not include magnetic monopoles magnetic forces are
| ALWAYS and ONLY exerted at right angles to the velocity of
| moving, electrically charged objects. The fact that they,
| therefore, "do no work" is a trivial and direct result.
John, I'm interpreting what you said (above as well as in what I
snipped), as meaning that in dB/dt != 0 cases, as a matter of principle,
that it is the induced electric fields that do the work, not the
magnetic field. (in the classical world described above).
Correct me if I'm wrong.
_____________
PS,
I certainly appreciate John M.'s comments about the convenience of doing
calculations in other ways.