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Re: poundals



Actually, I think a poundal is a force.

I don't believe we have a single word for a mass that weighs one pound,
just like we don't have a word for a mass that weighs one newton.

I believe we call a mass with a standard weight of one pound by the
name one "pound-mass."

The poundal is then the force that will give a one pound-mass mass an
acceleration of one foot-per-second-squared.

Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817



-----Original Message-----
From: John Denker [SMTP:jsd@MONMOUTH.COM]
Sent: Monday, October 18, 1999 10:34 AM
To: PHYS-L@lists.nau.edu
Subject: poundals

At 09:47 AM 10/18/99 -0400, Michael Edmiston wrote:

When we had balances reading only in grams, we didn't have the new
problem of "balances" that can give readings in ounces, pounds,
newtons, etc. Some do not offer readings in newtons, and they
interpret ounces and pounds as "ounce-mass" and "pound-mass."

There is a creature called a _poundal_ which is a unit of mass, defined
to
be equal to 0.45359 kilograms. This is useful (pedagogically and
practically) when one wants a unit of mass that corresponds to the
vernacular notion of "a pound of stuff" while preserving the pound as a
unit of force. I suppose we could define an "ouncel" similarly.

Sad note: The Random House Dictionary of the English Language
(otherwise
an unusually fine dictionary) gets this exactly horribly backwards,
speaking of poundals of force and pounds of mass. Yecchhhhh.


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