Re: A maximum possible acceleration ?

[brian whatcott <inet@intellisys.net>]

There is an answer as to a limiting value of x'' which you will find
disappointing:
 for people exploring the possibility of storing energy in flywheels,
it is convenient to refer to a figure of merit which is applicable
 to a particular material; this figure capsulates the maximal rotational 
rate before a given wheel mass explosively comes apart, a specific 
energy-density, so to speak. This is a 'strength of materials' issue,
and motivates the choice of wrapped carbon-fiber rather than steel.
Regards
Brian

At 09:51 11/29/97 -0400, you 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
brian whatcott <inet@intellisys.net>
Altus OK