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Re: Pb



At 2:04 PM -0500 3/9/01, Andy Dougherty wrote:
On Fri, 9 Mar 2001, Jim Green wrote:

Suppose I drop a piece of lead. The Earth, via gravity, does positive work
on the lead and increases its KE. OK? The lead hits the floor; the flood
does negative work on the lead; the lead halts. KE->0 OK? Does Wgravity =
Wfloor?

Yes, if you define W_floor such that it equals W_gravity.
No, if you define W_floor such that it does not equal W_gravity.

Defining "The Work" done by one deformable object on another deformable
object is a tricky business that tends to generate a lot of "heat" on this
list but usually very little light.

I disagree. I have enjoyed and profited from each of this list's
excursions down this path.

Do we really need to go there again
so soon after our last trek down this path?

As long as there is still understanding to be shared and gained, I would
say yes.

The "heat" discussions have been controversial and difficult, but I think
each round makes things a tiny bit clearer. Some people gain new insight,
and those that don't at least more clearly understand their and others'
positions--even where agreement is not reached.

Larry