ABSTRACT
Consider a charge q′ held fixed at a point r′ and another charge q which moves in its electric field. In Newtonian mechanics, the equation of motion will be given by
m d2r
dt2 =
qq′
4π
r − r′ |r − r′|3 , (6.1)
where m is the mass of the charge q and r denotes its instantaneous position. Looking at this equation, we immediately notice that there are certain discrete symmetries that it possesses. These are listed below.
