Lester Zick says...
"George Dishman" wrote:

The same is true in Newtonian physics, the kinetic
energy of an object is zero in its rest frame
and the value diffes from frame to frame regardless
of what theory you use.

Nonsense, George. There is only one frame of reference in Newtonian
physics, a universal isometric Euclidean-Galilean-Cartesian-Newtonian
frame of reference whose origin can change but whose metric properties
remain constant unlike second order velocitiy dependent anisometric
properties of reference frames in SR.

What in the world are you talking about, Lester? Newtonian physics
certainly has a notion of different frames of reference. That's what
the Galilean transformations are about:

x' = x - vt

Velocity, momentum, kinetic energy are all frame-dependent quantities
in Newtonian physics. The Newtonian notion of "frame of reference" is
pretty much the same as in Special Relativity. I usually prefer not
to mention frames of reference, and just talk about coordinate systems,
but as it is usually used, a frame of reference is a standard for which
objects are "at rest" and which are not. It's sometimes called a "rest
frame" for that reason. A frame of reference usually also provides a
standard for measuring the distances between events (whether or not
they take place at the same time). It's not exactly the same thing
as a coordinate system, however, because a frame of reference doesn't
specify what is the origin, or what the coordinate axes are.

--
Daryl McCullough
Ithaca, NY