Re: PseudoWork ????

[Bob Sciamanda <trebor@VELOCITY.NET>]

I don't think this will do, Jim.  Your model must also apply to the
limiting case (mass of earth/wall => oo)!
In this limit, the wall is stationary, but I (the pusher) still gain CM
kinetic energy from only energy sources/transformations inside myself!

Bob

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor

----- Original Message -----
From: Jim Green <JMGreen@SISNA.COM>
To: <PHYS-L@lists.nau.edu>
Sent: Friday, October 29, 1999 12:51 PM
Subject: PseudoWork ????


> At 05:23 AM 29-10-99 -0400, Bob Sciamanda wrote:
> > Yes, Jim.  This is why I say that when you push off from a stationary
> > wall, the wall does work, even though the resulting energy of bulk
motion
> > came only from internal sources, not from the wall!
>
> Well, Bob, when someone says that he agrees with, you it is hard to
> disagree with him. (:-)
> Some want tp call this pseudowork we agree tht this is not helpful.  But
I
> would add the it is also true that there is no such thing as a
stationary
> wall.  If the pusher moves, so does the wall.  Now given the mass of the
> wall plus the Earth to which it is attached, the wall does not move very
> much, but it does move.  The wall does indeed do work on the pusher.
> . . . Jim