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Re: work done by pushing

At 01:16 AM 10/26/99 -0400, Bob Sciamanda wrote:

When I push myself away from a wall, the force from the wall does
work

That's not right.

(defined as its line integral over the displacement of my CM),

That's not the right definition of work; see below.

but the wall is not an energy source.

That's true.

============================

When we say "A does work on B" it means that energy is flowing across the
boundary between A and B. This is not happening when you push away from a
wall. At the boundary, there is no significant "F dot dx". The main place
where there is some "F dot dx" is at your shoulder, and we all agree that
your arm is doing work on your torso.

______________________________________________________________
copyright (C) 1999 John S. Denker jsd@monmouth.com