[amsat-bb] Re: AMSAT-NA totally metric?

[Bruce Bostwick <lihan161051@xxxxxxxxxxxxx>]

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  
those.)

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.



_______________________________________________
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb