Re: [Phys-l] momentum and energy

[Jack Uretsky <jlu@hep.anl.gov>]

Hi all-
	It is much more than just some "cute mathematics".  As Feynman has 
stressed, it is the idealizations that make physics (and, probably, 
science and engineering in general) doable.  We abstract the key elements 
from very complex situations that allow us to approximately reproduce the 
situations we desire.  That is why not every airplane is in its final form 
at the time of its first flight.
				Regards,
					Jack







On Wed, 15 Nov 2006, Al Bachman wrote:

> bc forgot that it is the momentum transfer that is constant, not V.
>
> IMHO one should not push the topic of elastic collisions too much.
> They are an idealized case that results in some "cute" mathematics.
>
> All materials are deformable (atoms separated by forces that vary with
> relative position). Thermalization, dissipation and permanent deformations
> all occur. Just think of the energy propagated as noise in a collision!
>
> Al Bachman
>  ----- Original Message -----
>  From: Bernard Cleyet<mailto:bernardcleyet@redshift.com>
>  To: Forum for Physics Educators<mailto:phys-l@carnot.physics.buffalo.edu>
>  Sent: Tuesday, November 14, 2006 11:43 PM
>  Subject: Re: [Phys-l] momentum and energy
>
>
>  Classically (N)  p^2/2m = (identically)  m^2* V^2 / 2 m    Am I crazy?
>
>
>  If not, then,  lim:  m => inf.      (with v non zero*)   E => .    not zero
>
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