[amsat-bb] Re: AMSAT-NA totally metric?
lihan161051 at sbcglobal.net
Sun Jan 21 06:44:44 PST 2007
Speaking of energy .. one thing I wish would come into common usage,
because I've found it really handy for comparison purposes, is
expressing energy in joules (one of my favorite SI units), because
it's both a newton-meter of work (not a newton-meter of torque! :)
and a watt-second of energy. Outside the scientific community,
energy is referred to as everything from BTU (heating/cooling) to
gallons of gasoline (automotive) to tons of TNT (nuclear weapons) to
foot-pounds of work (ballistics), it's enough to make an empirical
skilled generalist's head spin. (And I know I'm not the only one of
And yes, a liter of water is a kilogram, by definition, since the
gram was originally defined (IIRC) as the mass of a cubic centimeter
(i.e. milliliter) of water. (The kilogram is one of the few units
still referenced to a physical standard object kept at the
International Bureau of Weights and Measures, interestingly enough.
The meter used to be referenced to a standard meter bar kept at the
same bureau, but has now been defined by a quantum standard that
doesn't require reference to a physical object.)
On Jan 20, 2007, at 11:02 PM, laura halliday wrote:
> It's so much easier in metric, where a kilogram is
> very much a unit of mass, while force is measured
> in newtons...and let's not worry about ergs and dynes
> and things: SI is mks.
ENGLISH: A language that lurks in dark alleys, beats up other
languages, and rifles through their pockets for spare vocabulary.
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