Re: [Phys-l] conservation versus constancy

[Bernard Cleyet <bernardcleyet@redshift.com>]

I think it's understood that the application of conservation is to 
before and after a processes, not during.

I suspect the only example of "perfect" elasticity is elastic atomic 
collisions and other similar "particles".  Otherwise, one may 
arbitrarily assign as elastic a collision if, say, 99% of the initial KE 
is found after, e.g. glass on glass at low energy (no chipping, etc.).  
Another, maybe, is a moving magnet colliding w/ a rigidly fixed magnet 
and no "physical" contact.

bc, who wonders what the KE loss is in the case of "sling shot" space 
probe manoeuvres.

p.s. correction:  96% probably more realistic: [Scroll to bottom.]

http://www.csun.edu/~lg48405/virtual/trackB/KIM/hk.literature_review.html 
<http://www.csun.edu/%7Elg48405/virtual/trackB/KIM/hk.literature_review.html>



Spinoza321@aol.com wrote:

> In a message dated 10/16/2006 12:40:40 PM Eastern Standard Time,  
> Spinoza321@aol.com writes:
>
>
> In a  message dated 10/16/2006 11:21:16 AM Eastern Standard Time,   
> rlamont@postoffice.providence.edu writes:
>
> Again,  Not to  nit-pick, but:
>
> KE is neither "constant" nor "conserved". In  fact,  during the actual elastic
> collision it can practically disappear.   It's really a matter of how much of
> it reappears as gross KE and how  much  as microscopic KE after the contact
> phase of the  collision.
>
> Bob at  PC
>
>
>
>
>
>
> By definition  elastic collisions conserve KE,  inelastic collisions  don't. 
> So  what are you saying here?
>
> Bob Zannelli 
>
>
>
>
>
> Never mind. You are talking about during the actual time interval of the  
> collision. Sorry.
>
> Bob Zannelli 
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