[SciPy-User] Error in constants documentation?
Arthur M. Greene
Tue Apr 6 15:08:53 CDT 2010
It would seem that there is some confusion, in the
constants.html, between force and mass...
Strictly speaking, kg is a unit of mass, Newton a unit
of force. Weight is force, not mass: A gold brick
floating in interstellar space is weightless but still
massive. Pounds and kilograms can be equated, but only
in some specified gravitational field (like at the
surface of the earth, where we usually weigh things).
So mass is the more fundamental quantity, since it does
not depend on gravity for its value. In Imperial units
(feet, pounds) the unit of mass is the slug:
http://en.wikipedia.org/wiki/Slug_(mass). This is
absent from the constants page.
Warren Weckesser wrote:
> Florian Lindner wrote:
>> http://docs.scipy.org/doc/scipy-0.7.x/reference/constants.html chapter Force says:
>> dyn one dyne in watts
>> lbf one pound force in watts
>> kgf one kilogram force in watts
>> doesn't the watts actually have to newtons as the unit of force?
> There is a ticket with the same question here:
>> SciPy-User mailing list
> SciPy-User mailing list
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