Re: pinhole Hewitt and circular motion

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From: Steven Eiger (eiger@montana.edu)
Date: Sat Dec 11 1999 - 05:49:12 PST 

Message-Id: <l03102804b4780650c71b@[153.90.241.107]>
Date: Sat, 11 Dec 1999 07:49:12 -0600
From: Steven Eiger <eiger@montana.edu>
Subject: Re: pinhole Hewitt and circular motion

NO, it is not English. Work is force times distance in the direction of
the applied force. Since the direction travelled is always perfectly
perpendicular to the force, there is no work done, and a good thing too, or
we would both loose a lot of energy.

>Is it the English again?
>
>In a concept development exercise from Conceptual
>Physics (14-1 in 2nd edition, 12-1 in 1st edition), a
>question arises whether work is done on the moon as it
>orbits the Earth. The answer given is that no work is
>done. Can somebody give me an easy explanation? If
>there were no force of gravity the moon would not be
>in orbit, so work must be done, mustn't it? The
>distance that the moon travels perpendicular to the
>force is equal to the distance the moon falls due to
>the force so the moon stays in orbit, and thus there
>is a force through a distance which is physical work,
>n'est ce pas? Either I am musunderstanding the
>physical definition of work or I must be daft.
>
>-Marc
>
>
>
>=====
>Marc Afifi
>Chemistry, Physics, Marine Science
>Pacific Grove High School
>Pacific Grove, CA
>
>http://www.pghs.org/staff/afifi/d5hp.html
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Steven Eiger, Ph.D.

Departments of Biology and the WWAMI Medical Education Program
Montana State University - Bozeman
Bozeman, MT 59717-3460

Voice: (406) 994-5672
E-mail: eiger@montana.edu
FAX: (406) 994-3190

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