A vetor diagram in my mind evolves around Newtons laws
All forces (vectors) forces when summed must equal zero.
Whether their is a triange or a polygon of forces it always leaves a
gap
whuch thus provides a vector required to make he arrangement equal
zero
and in a state of equilibrium. The masters always followed this
aproach to determine if equilibrium
was present by vectorizing all the forces known within a arbitrary
border. They always came up with
an unclosed vector arrangement even tho it met the requirements of
equilibrium. So all filled in the gap
o arrive at the starting point and labelled this unknown vector that
they were forced to provide as the weak force required for equilibrium
to satisfy Newtons law.
Regards
Art

I think you are confusing the "Weak force", resposible for "Beta decay"
in radio-active materials. The following web site explains the work
of Enrico Fermi in this area:
http://atomic-molecular-optical-phys...the_weak_force
While it is not unreasonable to consider Newtonian mechanics in
an explanation of what hapens within a conductor, there is no
missing force involved.

Computation of the electric and magnetic fields in the vicinity of a
conductor involve manipulation of the "Vector magnetic potential";
as in:
http://en.wikipedia.org/wiki/Magnetic_vector_potential

Frank