Consider the expression,
x.mv
Differentiating wrt t,
d(x.mv)dt=dxdtmv+xd(mv)dt=mv2+x.F
where,
F=d(mv)dt, v=dxdt
When x.mv is periodic over period T,
x.mv=∫T0mv2+x.Fdt=(mv2+x.F)T
where mv2+x.F is assumed constant over t and
f=1T
Let,
h=x.mv
then,
hf=E=mv2+x.F
But,
E≠mv2+x.F.
E=KE+PE
What happened? From the post "Not A Wave, But Work Done!" when v=c,
∂ψ∂t=2∂V∂t=2∂T∂t
We have
V=T+C
where C is the constant of integration after integrating over t.
If C=0, ie there is no bias in oscillation as ψ interchange between V and T. Then,
V=T
If a particle is in circulation at velocity v=c,
T=12mc2
and so,
U=T=12mc2 and so,
ψ=U+T=mc2
In which case,
hf=mc2+x.F=ψ+x.F
E=ψ+x.F
That is to say, E is the energy of the particle plus work done on it. As long as F acts within the period T, the integration over t=T is valid. A collision or a photon passing at light speed are within this assumption.
The assumption that C=0, also applies to E, as such C=0 is just assuming a reference potential of zero in a system.
Why is x.F called the work function before it was worked out as work done by a force?