FFF system

Source: Wikipedia, the free encyclopedia.

The furlong–firkin–fortnight (FFF) system is a

metre–kilogram–second systems, there are derived units for velocity, volume, mass and weight, etc. It is sometimes referred as the FFFF system where the fourth 'F' is degrees Fahrenheit
for temperature.

While the FFF system is not used in practice it has been used as an example in discussions of the relative merits of different systems of units.

unit conversion and dimensional analysis.[5][6]

Base units and definitions

Unit Abbreviation Dimension
SI
unit 		Imperial unit
furlong fur length 201.168 m 220 yards
firkin fir mass 40.8233133 kg 90
lb[a]
fortnight ftn time 1,209,600 s 14 days

Notable multiples and derived units

Microfortnight and other decimal prefixes

One microfortnight is equal to 1.2096 seconds.[2] This has become a joke in computer science because in the VMS operating system, the TIMEPROMPTWAIT variable, which holds the time the system will wait for an operator to set the correct date and time at boot if it realizes that the current value is invalid, is set in microfortnights. This is because the computer uses a loop instead of the internal clock, which has not been activated yet to run the timer.[7] The documentation notes that "[t]he time unit of micro-fortnights is approximated as seconds in the implementation".[8]

The Jargon File reports that the millifortnight (about 20 minutes) and nanofortnight have been occasionally used.[7]

Furlong per fortnight

One furlong per fortnight is a speed that would be barely noticeable to the naked eye. It converts to:

  • 1.663×10−4
    m/s
    , (i.e. 0.1663 mm/s),
  • roughly 1 cm/min (to within 1 part in 400),[b]
  • 5.987×10−4 km/h,
  • roughly 3⁄8 in/min,
  • 3.720×10−4 mph,
  • the speed of the tip of a 3+3⁄4 inch minute hand.

Speed of light

The

joules
).

Others

In the FFF system,

Thermal conductivity
has units of BTU per fortnight per furlong per degree Fahrenheit.

Like the more common furlong per fortnight,[4] a firkin per fortnight can refer to "any obscure unit".[10]

See also

Footnotes

  1. imperial firkin (9 imp gal
    ) of water. The imperial gallon was originally defined as the volume of 10 lb of distilled water (weighed according to specific conditions). From this definition a density of 10 lb/imp gal is derived, giving the firkin of water a mass of 90 lb.
  2. ^ Indeed, if the inch were defined as 2.5454... cm, it would be 1 cm/min[9]
  3. ^ The foot-fathom is a unit of area; 1 foot-fathom is equal to 6 square feet.

References

  1. ^
    doi:10.1145/1229899.1229919
  2. ^
    ISBN 1-59749-115-2
    .
  3. JSTOR 3027087
    .
  4. ^
    ISBN 978-0-7506-8644-0
    .
  5. ISBN 0-07-052407-6
    .
  6. ISBN 978-0-13-606442-8
    .
  7. ^ a b "microfortnight". Retrieved 2007-07-06.
  8. ^ "HP OpenVMS System Management Utilities Reference Manual". 2001-03-30. Archived from the original on 2024-02-07.
  9. ^ "FAQ for newsgroup UK.rec.sheds, version 2&3/7th". 2000. Archived from the original (TXT) on 2006-03-06. Retrieved 2006-03-10.
  10. ISBN 0-201-69946-X
    .
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