Yes, Jeff, I drive a Ford...a 1990 Taurus...and yes, it has mixed stuff under the hood...though the whole engine is Metric, which caused me all kinds of grief because the metric sizes are not standardized the way the SAE ones are...but that's another story.
The point is, "because everybody else is doing it" is seldom a good reason to do anything. The conversion argument is also rather tiresome, as regardless of what system of units I am using, in the real world I don't often have to do conversions. The board I cut for my roof last night is 34-1/2 inches long and 5-1/2 inches wide. The Coke I drank from a 16-ounce mug came out of a 2-liter bottle. The pizza I ate was a Large. Cedar Point is 110 miles away, my fishtank holds ten gallons. It is seldom ever necessary to do conversions. Math geeks will note that the roof board should have been 2 feet 10-1/2 inches long and that my mug holds a pint. But doggone it, it isn't necessary, and my tape measure is marked off in 1/16-inch increments, so I'll measure the board in inches. And lest you believe (incorrectly) that this is because it is too complicated to divide by twelve, I should point out that it is common practice in Metric construction to do the same thing: to specify the construction measurements in millimeters.
Which brings up another interesting point...Metric measurements add a serious possibility for error because of the base-10 unit conversion...a misplaced decimal point will give you a number that looks right but is off by a factor of 10...which is why construction standardizes on millimeters or centimeters when meters might make more sense.
Putting all that aside, the important thing is that the standard of measurement is not really of more than political importance. The important thing is that whenever a measurement is given, the units of that measurement MUST be given, and the conversion factor needs to be consistent. Measurements should be done using convenient and appropriate units, but most important those measurements must be specified. Heck, I can remember a Physics class where I measured the height of a tall structure in Kedometers (Km), which was the length of the sneaker I was wearing that day (it worked out to 1 Km = 11.5 inches, and the object proved to be 62' tall).
--Dave Althoff, Jr.
You know, given that 2.54 cm equals exactly 1"... there should never be a problem going from English to Metric. They have a defined equality.
Hence, it's a matter of whether you prefer base-10 or Dave's inherent sense of scaling.
and I never did understand wet and dry weights, and Metric's insistance on using 'mass' terms to describe 'weight'.
It's Newtons, people, not kilograms!
Yeah, I don't get that either, plus how do they measure mass?-with the assistance of gravity-oh wait, that SHOULD be weight. So basically a triple beam balance on earth would be pointless to use at abnormally high altitudes, the moon, or anything like that. I guess they just like kilograms and grams more.
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Trim brakes-a necessity???
(This is so far off-topic I am surprised that Jeff hasn't put a stop to it yet...)
As for why the kilogram is typically used instead of the Newton...
My best guess is that the Newton is in fact defined in terms of the kilogram...a Newton is a kilogram-meter-per-second. A kilogram is a mass equal to the mass of a particular platinum-iridium cylinder of a particular size stored in a vacuum jar in France. The other thing is, the kilogram gives a more useful number than the Newton. Assuming I am doing the math correctly, I weigh about 240 pounds, which makes me about 109 kg, which should be about 1,067 N...
--Dave Althoff, Jr.