Moses wrote:
" . . . Finally, and perhaps most important, [1] is, in turn, corollary of
E(v)=m(v)c^2. In other words, these two equations are mathematically
equivalent. Therefore, if we accept [1], we cannot discard E(v)=m(v)c^2 as
generalized mass-energy equivalence, with mass m(v) being the measure of
object's inertia experimentally determined by its acceleration under given
force transverse to instantaneous 3-velocity. For those who prefer
abstract-mathematical formulations, it may be more convenient to define the
rest mass as a numerical factor converting 4-velocity into 4-momentum,
whereas the relativistic mass is a factor converting 3-velocity into
3-momentum. As far as we regard 3-velocity and 3-momentum as important
physical observables, and want to be consistent, we must attribute the same
status to relativistic mass. "
Moses Fayngold,NJIT
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Moses, I applaud your cogent observations regarding the usefulness of the
relativistic mass concept. The belittling of alternate conceptual
interpretations of mathematical models should be anathema in physics
discussions - it smacks of the tactic of demonizing opposing views - common
in political wrangling. Let us acknowledge the possibility of alternate
views and practice the "de gustibus . . ." which we are wont to preach. I
find the concepts of time dilation, length contraction and relativistic mass
very useful conceptual interpretations of our mathematical models.
Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
treborsci@verizon.net
www.sciamanda.com