Re: positive and negative work

[Rick Tarara <rtarara@SAINTMARYS.EDU>]

----- Original Message -----
From: "Gene Mosca" <mosca@USNA.EDU>


> I agree with John Denker that the leg muscles do negative work.  If a
muscle
> contracts under tension it does positive work, if it lengthens it does
> negative work.  The muscles in the front of the thigh are under tension
and
> lengthen as you sit.
I sort of mentioned this earlier, but what if one was suspended upside down
from the feet.
1)  Could you use your leg muscles to pull into an inverted sitting
position?
2)  If you could, would the contractions and expansions of the muscles be
the same as when normally sitting?
3)  Since the center of mass would be raised, positive work has been
done --by what?

Of course if the answer to 1) is no, then 2 & 3 are mute.  I don't have the
facilities (nor am I any the kind of shape) to try!  ;-)

Rick

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Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, IN 46556
rtarara@saintmarys.edu

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