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Re: Around inertial frames in circles (fwd)




In the previous discussion one point was allowed to get by which really
should not go unchallenged:

On Tue, 23 Apr 1996 JegaA@aol.com wrote:
...
We never observe a force -- only 'its' effects. Force, I believe, is
human construct that permits us to 'make sense' of what we perceive ...

This of course can be said of everything with equal validity, and because
it can be said of everything, it adds nothing to the discussion of force.
For example, in the wiew espoused above, we never observe chairs or tables,
only their effects. I say this, because both chairs and tables and, say,
the force the ground exerts on my feet are only detected through the effects
on membranes of my body (retina, skin) caused by photons of the
electromagnetic field. We have the same physical explanation of both, which
will stand or fall equally for both. The philosophical discussion, while
interesting in it's own right and appropriate for another list, adds nothing
to the astronomy or the physics of the situation.

The fact remains that forces can kill you and accelerations cannot, and
renaming accelerations to be forces by decree cannot change that situation,
any more than wishes will allow beggers to ride.

As I mentioned at the beginning of this thread, it has been rehashed
previously, and is in the archives presumably, but it will probably keep
cropping up periodically. It seems important to me not to let it slide by
on the astronomy list, because only bad astronomy is going to follow from
bad physics. And it is definitely bad physics to try to apply Newton's laws
in any frames other than inertial frames; of course, you can transform to
any noninertrial frame you wish -- just don't expect that Newton's laws
will be valid in such frames (or Einstein's laws, for that matter,
either) with detectable corresponding forces, i. e., in the terms introduced
above, forces with detectable effects.


A. R. Marlow