[Phys-L] Re: collision question

[Herbert H Gottlieb <herbgottlieb@JUNO.COM>]

Forget collisions. Let's make it a bit more simple:
If it takes mechanical energy to step on an empty tin can and crush it,
Some of this energy is released as heat to the surroundings during the
crushing. Where does the rest of the energy go?


On Fri, 18 Feb 2005 12:39:21 -0500 Bob Sciamanda <trebor@WINBEAM.COM>
writes:
> Certainly, the momentum of the entire closed system is conserved.  So
> is the
> energy.  This does not preclude dissipation.  Dissipation of energy
> does not
> imply energy destruction - neither does dissipation of momentum.
> (The original system momentum is not necessarily zero, but that is a
> red
> herring)
>
> Bob Sciamanda
> Physics, Edinboro Univ of PA (Em)
> http://www.winbeam.com/~trebor/
> trebor@winbeam.com
> ----- Original Message -----
> From: "Scott Goelzer" <s.goelzer@COMCAST.NET>
> To: <PHYS-L@LISTS.NAU.EDU>
> Sent: Friday, February 18, 2005 12:00 PM
> Subject: Re: collision question
>
>
> | On Feb 18, 2005, at 9:30 AM, Bob Sciamanda wrote:
> |
> | >
> | >
> | > Two electrons flying by (while repelling) each other, generate
> E/M
> | > radiation
> | > fields which carry away momentum/energy.  This momentum/energy
> is lost
> | > to
> | > the two particle system and is ultimately absorbed and
> thermalized by
> | > the
> | > lab walls and/or other objects.  Why can I not say that
> | > momentum/energy has
> | > been dissipated by the two particle system?
> | >
> | >
> |
> | I'll give it a shot.
> | Initially there was no momentum , then as the electrons pushed
> away
> | from each other there is still zero total momentum since p is a
> vector.
> | If the room is included in the system, then after the electrons
> | interact with the room, the total momentum remains zero and the CM
> is
> | not changed. Individual momentums did not dissipate , they
> cancelled.
> |
> | Scott
> |
> |
> |
> | **********************************
> | Scott Goelzer
> | Physics Teacher
> | Coe-Brown Northwood Academy
> | Northwood NH 03261
> | 603-942-5531e218
> | sgoelzer@coebrownacademy.com
> | **********************************
> |
> |


Herb Gottlieb from New York City
A friendly  place to live and visit