Dear Joe,

Thanks for that. It had never occurred to me to think who were the first to
need the slug as a more practical unit of mass.

Cheers,

Pat Naughtin CAMS
Geelong, Australia

on 2002-11-15 12.22, Joseph B. Reid at [EMAIL PROTECTED] wrote:

> I believe that the slug as a unit of mass was invented by the
> aeronautical engineers.  They clung to the pound-force, because
> historically gravity was the only force civil engineers were
> concerned with.  The aeronautical engineers had to deal with
> accelerations quite different from the acceleration due to gravity,
> and so they invented the slug = 32.2 pounds-mass. Thus
>     force (pounds-force) = mass x acceleration (slugs x feet/second squared).
> I first met the slug at the Royal Aircraft Establishment. Physicists
> were quite happy with the pound-mass so they invented the poundal =
> (1/32.2) pound-force. Thus:
>     force (poundals) = mass x acceleration (pounds-mass x
> feet/second squared).

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