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Re: A maximum possible acceleration ?



Hi,
If you want to attack this from the modern physics side,
consider Compton scattering, but from the QED or Feyman diagram point of
view. In this point of view, acceleration is meaningless in that one
does not actually deal with "what happens" at the vertex where the world
lines meet. Acceleration is instantaeous in that two things meet,
vanish, and a new third entity with a mometum different than the
previous entities appears.

Ludwik, I am concerned that you are mixing derviatives (dx) with
minimum theoretical uncertainities (Delta x). These are not the same in
any size shape or form. It is also a bit
worrisome to see idealized classical mechanics mixed with quantum
mechanics. Prefectly rigid stuff requires infinite forces within the
stuff! QM will complain.

Thanks
Roger Haar


**********************************************************
LUDWIK KOWALSKI wrote:

We learn in Modern Physics that:

dx*dp ~ h_ uncertainty of x h_ = lower limit of this product
dt*dE ~ h_ uncertainty of t h_ = also a lower limit of product
(dx/dt) < c c speed of light c = the upper limit of v (ratio)

The existance of an upper limit for the first derivative suggests (?)
that the second derivative (acceleration --> force) may also have an
upper limit. I never heard about this, except in the context that a
physical quantity can not change in zero time. What principles would
be violated by allowing too rapid change in v? (What kind of "inertia"

would prevent this? What kind of "Lenz law" would be ... ?)

Is there a formal limit for the second derivative of position with
respect of time somewhere ? (in general relativity? in QCD? ...).

Ludwik Kowalski