Martin Posted September 18, 2004 Posted September 18, 2004 It's proposed that SFN have an honorary system of units besides the standard SI metric ones. In the proposed system major physical constants will have values which are powers of ten. A growing number of people these days are using 8pi times G, possible nickname "Gbar", instead of G and Planck units seem on the way to being redefined so as to make |Gbar| = |c| = |hbar| = |k| = 1 so it was decided to make Gbar, instead of plain G, be a power of ten. Anyway, you set these things to be reasonable powers of ten and that determines what the everyday-scale units have to be mass unit----pound-size---call it pound length unit----handwidth size----call it hand time unit----222 to a minute----call it count (people can count aloud 222 to the minute) force unit---half a newton, two ounce force----call it "dram" what should the energy unit be called? by analogy with "foot pound" unit of work, push foot distance with pound force, it could be called "hand dram"----push for handwidth distance with dram (half a newton) force---but that doesnt sound so good. should it be called a JOT of work? as in "she just lay on the couch and read novels, didnt do a jot of work all day" a jot is a very small amount of energy---the handwidth unit is 8.09 centimeters and the dram force is around 0.48 newtons so this is around 0.04 joules or 1/100 of a calorie! on the other hand even small quantities (joule, pascal) are named in honor of people. so maybe this energy unit should be called after one of us. Any suggestions? Anyway, thought it should be opened for discussion.
Martin Posted September 18, 2004 Author Posted September 18, 2004 the good thing about SFN units is that major constants are powers of ten the units are defined by assigning these values to the constants Gbar = 10-7 hand3count-2pound-1 c = 109 hand count-1 hbar = 10-32 jot count k = 10-22 jot degree-1 [think of the word "jot" as a placeholder, it is this word for the energy unit that I'm asking you to think of a replacement for] In conventional metric, c = 2.99792458 x 108 meter second-1 and the other constants are even messier, so there's some attraction to SFN units getting simple powers of ten for the constants. with the above powers of ten stipulated then the time unit (count) comes out 222 to the minute. the temperature degree turns out to be about half a Fahrenheit the mass unit comes out to 434 grams, roughly like a pound. the length unit is 8.09 centimeters (around 3 and 1/4 inches) the force unit (if that much accuracy is desired) is 0.4816 newton.
jordan Posted September 18, 2004 Posted September 18, 2004 Doesn't the world have enough different units as it is?
Martin Posted September 18, 2004 Author Posted September 18, 2004 Doesn't the world have enough different units as it is? physicists keep on devising more sets of units, so from a pragmatic standpoint one has to say no, there are evidently not enough yet to satisfy everybody besides the conventional metric (which I dont see being used much in theoretical physics papers) there is the "atomic units" and then experimentalists often talk in eevee (temperatures, masses, wavelengths, energies all given in eV, MeV, ...etc) and there are QED units for doing quantum electrodynamics and QFT units for quantum field theory and more and more people now seem to be using Planck units! (these would be the preferred set in any quantum theory of gravity, any scheme to merge QM and GR) the fact is that humans have not settled on one monolithic system, as yet. the world might be prettier if they did
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