Are Newton's three laws of motion essentially correct

[Antonio Lao]

But for all relativistic mechanics, it is the square of energy that can describe the linear momentum of light

E^2 = c^2 \mathbf{p}^2 + m^2 c^4

when the mass is zero, such as that for a photon, its energy becomes purely kinetic, then its momentum is

p =\frac{E}{c}

this implies that when mass is zero, the momentum turns from a vector into a scalar at the maximum speed of c. In other words, the photon has none of that directional properties. Its is motionless. So applying Newton's 1st law, the photon is either at rest or moving at a constant speed of c in an inertial frame of reference.

 

[InvariantBrian]

The virial theorem says that <T> = <V>/2, so the kinetic energy is
double the potential for a 1/r potentialv Also,we know that Newton's Third law works for gravity, which is a 1/r potential.

 

[InvariantBrian]

In order to do this RIGHT you need to use 4 vector analysis which does
indeed have directions to it. The E = p*c is the magnitude of the
momentum. What is right is E = sqrt(p^2*c^2) where p^2 is really the
inner product of the regular momentum (as a vector).

 

[Antonio Lao]

Thanks for the math. Gonna work on it some more till I am eligible for a PhD.