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

[Bob Sciamanda <trebor@VELOCITY.NET>]

David,
I retract my statement #2, below.  It is wrong.  You are indeed correct in
the assertion that the accelerations of the two electrons are equal and
opposite - as measured in their CM frame.  This fact, however does NOT make
the CM frame an inertial frame.
 Bob

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
www.velocity.net/~trebor
----- Original Message -----
From: "Bob Sciamanda" <trebor@VELOCITY.NET>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, June 18, 2001 11:41 PM
Subject: Re: 4/3 problem resolution/Action-reaction paradox in pdf format


> 1.)  I think you nave agreed that the accelerations of the two electrons
are
> not equal and opposite in the (inertial) lab frame.
>
> 2.)  At least for non-relativistic velocities, simply subtracting the CM
> acceleration (as measured in the lab frame) from these electron lab
> accelerations gives their accelerations in the CM frame.  They will
clearly
> not be equal and opposite in the CM frame either.
>
> 3.)  Your statement:
>
> > "Thus, the center of mass of the electrons is stationary, from the
> viewpoint of an observer
>  >at rest in the CM frame, so the CM frame is inertial."
>
> isn't even wrong! (borrowing from Pauli) - it is inscrutable; please
rethink
> it carefully.  This does not make a frame inertial!
>
> 4.)  Your words seem to imply that the CM frame is non-inertial as viewed
> from the lab, but is inertial as viewed from the CM frame itself.  A frame
> is either inertial or non-inertial, period.  This property (inertial vs
> non-inertial) is invariant.  Your argument seems to endow every frame with
> the "inertial frame property" to an observer at rest in that frame - not
so!
> Here lies self-contradictory madness!
>
> 5.)  Your symmetry arguments about the fields and forces omit the fact
that
> the accelerations of the two electrons are not equal and opposite.  Thus
> their fields (and forces) do not have the symmetry you suppose in your
> argument.  The electrons' fields are a function of position, velocity AND
> acceleration.  Feynman warned about this in developing the equations you
are
> using.
>
> Bob Sciamanda (W3NLV)
> Physics, Edinboro Univ of PA (em)
> trebor@velocity.net
> www.velocity.net/~trebor
> ----- Original Message -----
> From: "David Rutherford" <drutherford@SOFTCOM.NET>
> To: <PHYS-L@lists.nau.edu>
> Sent: Monday, June 18, 2001 5:05 PM
> Subject: Re: 4/3 problem resolution/Action-reaction paradox in pdf format
>
>
> > On Mon, 18 Jun 2001 10:13:02 -0400, Bob Sciamanda <trebor@VELOCITY.NET>
> >
> > wrote:
> >
> > > David,
> > > You are using relations which Feynman developed for a charge moving at
a
> > > constant velocity, as viewed from an inertial frame (presumably your
lab
> > > frame).  The CM frame of your two interacting electrons is not
inertial.
> > Why do you say that the CM frame is not inertial? Take the center of
> > mass of the electrons as the origin of the CM frame. The forces on the
> > electrons, in the CM frame, are equal and opposite, therefore, the
> > electrons undergo equal and opposite accelerations. Thus, the center of
> > mass of the electrons is stationary, from the viewpoint of an observer
> > at rest in the CM frame, so the CM frame is inertial. But in the
> > (inertial) lab frame, the electrons don't undergo equal and opposite
> > accelerations, so the center of mass of the electrons is accelerating,
> > from the viewpoint of an observer at rest in the lab frame. Thus, the
> > center of mass of the particles is not inertial in the lab frame. You
> > can't have the center of mass of the particles accelerating in one
> > inertial frame (lab frame) and not accelerating in another inertial
> > frame (CM frame). That's a paradox.
> >
> > --
> > Dave Rutherford
> > "New Transformation Equations and the Electric Field Four-vector"
> > http://www.softcom.net/users/der555