Re: [Phys-l] Magnetic force and work

["Bob Sciamanda" <trebor@winbeam.com>]

Thanks for the catch, Carl.  I realized the problem as soon as I hit the 
send button.  Personally, I dislike the term "pseudowork".  I refer to it as 
"CM work".
I don't see anything "pseudo" about it.  ( My view is that work-energy 
theorems are based only on Newton's laws and should not be expected to 
include any notion of energy transfer.  That notion is added much later, 
logically.)

Sorry, let's not reopen that can of worms!

Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
http://www.winbeam.com/~trebor/
trebor@velocity.net
----- Original Message ----- 
From: "Carl Mungan" <mungan@usna.edu>
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>
Sent: Tuesday, March 28, 2006 1:17 PM
Subject: Re: [Phys-l] Magnetic force and work


> Bob S wrote:
>
> > 3) If I (on frictionless ice skates) push off from an infinitely
> > rigid wall, there is no energy transfer between the wall and me. The
> > work energy theorem here guarantees that the work done by the wall's
> > push is numerically equal to my increase in kinetic energy, but it
> > says nothing to identify the source of my kinetic energy increase.
>
> I should restrain myself.  After all, Bob undoubtedly knows what he
> means by this statement. And I can rephrase it into a valid statement
> by replacing "work" by "pseudowork" everywhere above, that is the
> normal force integrated over the displacement of the center of mass
> of the skater while he's in contact with the wall. This is not the
> work that appears in many formulations of the first law of thermo
> however. -Carl
> --
> Carl E. Mungan, Asst Prof of Physics  410-293-6680 (O) -3729 (F)
> Naval Academy Stop 9c, 572C Holloway Rd, Annapolis MD 21402-5002
> mailto:mungan@usna.edu     http://usna.edu/Users/physics/mungan/
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