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# Re: 4/3 problem resolution/Action-reaction paradox in pdf format

On Mon, 18 Jun 2001 23:05:58 -0400, Bob Sciamanda <trebor@VELOCITY.NET>
wrote:

----- Original Message -----
From: "David Rutherford" <drutherford@SOFTCOM.NET>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, June 18, 2001 4:56 PM
Subject: Re: 4/3 problem resolution/Action-reaction paradox in pdf format

On Mon, 18 Jun 2001 10:51:55 -0400, Bob Sciamanda <trebor@VELOCITY.NET>

wrote:

David,
Sorry, in my haste I did not notice the words "both frames" in your post
(below). The general proof shows that momentum is conserved in inertial
frames. We do not expect momentum to be conserved in non-inertial
frames.

Are you saying that the momentum of the particles+fields is not
conserved in non-inertial frames?

Yes!

Suppose I am in a room with a pool table on which sits a set of pool balls,
at rest with respect to the table and the room. If I now go into some
erratic motion (eg., do a somersault) so that I become a non-inertial
observer, I will observe that the momentum of the pool ball system changes
in time (is not conserved) as observed from my non-inerial frame. So why
should I expect the momentum of a fields+particles system to be constant as
viewed from my non-inertial frame?

Okay, I was just asking? But you seemed to have omitted the most important
part of my post. I would appreciate your response. Here it is,

You also wrote:
I'm aware of the traditional explanation, but no one has yet shown me
that the momentum of particles plus fields is conserved in both
frames, for the specific cases I gave.

The general proof exists in standard E/M texts (Jackson, Panofsky &
Phillips, etc)

These texts refer to the volume integral of e_0(ExB) as representing the
total field momentum. But, as has been shown (by Feynman and others),
this alone doesn't represent the total field momentum ( refer to
http://www.softcom.net/users/der555/elecmass.pdf ). Therefore, the
general proofs you refer to don't hold up.

--
Dave Rutherford
"New Transformation Equations and the Electric Field Four-vector"
http://www.softcom.net/users/der555