Single-Particle Electrodynamics - Assassination Science

e eradicated. For example, one may quite validly consider a classical model
of an electric dipole as two electric charges on the ends of a stick; if this is
shrunk to infinitesimal size, then it is pointlike, but arguably not structureless.
Mathematically, equating these two adjectives correponds to deeming
that any non-trivial function of zero extent be a delta function; but one may
also have derivatives of delta functions (as with the point dipole example
above) that are of zero extent.
However, the converse generalisation is arguably a reasonable one: any
object that is not pointlike must have some sort of “structure” keeping it a
finite size, even if, in some cases, this structure might be rather featureless.
2.3 Newtonian mechanics
The formulation of mechanics that is arguably the simplest to understand is
that originally set out by Newton, summarised at the head of this chapter.
In Newton’s way of reckoning, each body possesses a “quantity of matter”,
which we now refer to as its mass, m, and a “quantity of motion” [158],
p ≡ mv (2.1)
(where v is the velocity of the body), which does not change unless some
sensible force is applied to the body. This definition of force would be circular,
except for the fact that Newton prescribed the forces that should apply to
objects, as Laws of Nature. Of course, Newton himself only laid down a
law for gravitation, not one for electrodynamics, nor the laws by which the
“particles of bodies cohere in regular figures”; but from his comments above
we see that he believed that ultimately all of physics could be described in
terms of a few universal forces between elementary types of object.
We shall now review various elementary aspects of the Newtonian formulation
of mechanics. In some cases we shall make definitions that do not
accord with popular practice; these definitions are those the author feels are
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