Re: Cause and Effect

[John Denker <jsd@MONMOUTH.COM>]

At 10:33 AM 10/23/00 +0530, D.V.N.Sarma wrote:

> Is it possible to make
>
>                         f = ma
>
> bidirectional with out the above equivalence [between gravitation
> and accelerated frames]?

Yes.




This question has been asked several times in several guises.  I don't
understand why the question comes up at all.  As I said before, pick a
frame.  F=ma is an equation in that frame.  This applies to modern-physics
free-falling frames.  This applies equally well to classical-physics
frames, including the typical classroom frame, if you include the effects
of gravity in the usual way.

An equation is an equation.  All equations are symmetric.  Bidirectional.
Always have been, always will be.

If you want to express a nonsymmetric relationship, you'd better use
something other than the "equality" operator.  Possibilities include
        -- the arithmetic "greater-than" operator ">"
        -- the set-theory "subset" operator
        -- the Boolean implication operator "==>"
        -- the Algol assignment operator ":="
        -- and others.