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From: alexis@reed.UUCP (Alexis Dimitriadis)
Newsgroups: net.bio
Subject: Re: Up The Down Escalator
Message-ID: <1629@reed.UUCP>
Date: Fri, 7-Jun-85 22:49:26 EDT
Article-I.D.: reed.1629
Posted: Fri Jun  7 22:49:26 1985
Date-Received: Mon, 10-Jun-85 20:49:07 EDT
References: <237@ihnet.UUCP>
Reply-To: alexis@reed.UUCP (PUT YOUR NAME HERE)
Distribution: net
Organization: Reed College, Portland, Oregon
Lines: 33
Summary: 

In article <237@ihnet.UUCP> eklhad@ihnet.UUCP (K. A. Dahlke) writes:
> 	Suppose we have two men, X and Y.  X is climbing a long flight
> of stairs, while Y is climbing a down escalator.
> X has already begun his ascent, and is no longer accelerating.
> Y also has a constant velocity, namely 0 (relative to the building).
> As Y climbs up, the escalator moves down.
> The question, who is doing more work?
> I did not submit this question to net.physics, because I already
> know the physics answer.  X is traversing a distance, against a force,
> line integrals F.dS etc etc, and so X is doing work while Y is lazy.
> However, X and Y seem to be making the same movements, against the same force.

  Actually, physics does have the answer:  If you use, in each
case, the steps as a reference frame, you find that both men are doing
the same amount of work.  
  To use a "stationary" reference frame in the case of the escalator is
misleading, since an immobile man in the escalator is losing potential
energy in a stationary reference frame, but not in the reference frame
of the escalator.  Bot men are doing the same amount of work, it is the
work done by the escalator that causes the difference.

Alexis Dimitriadis
-- 
_______________________________________________
  As soon as I get a full time job, the opinions expressed above
will attach themselves to my employer, who will never be rid of
them again.

             alexis @ reed

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