There is the imperial/customary/international foot defined as 0.3048 m, and the surveyor’s foot defined as 1200/3937 m (aka .304800609601219202438404 m)
I think the most insane combination of units can be found in aviation. They use feet for altitude but nautical miles for distance, then they use knots (nautical miles per hour) for horizontal velocity, but for vertical velocity they use feet per minute.
The nautical mile comes from the measure of 1 second of arc (°,mn,s) of longitude over the earth. Hence British nautical and French nautical mile conversion were slightly different as they were not defined at the same latitude.
That explains why the people who designed the meter found it logical for it to represent a portion of Earth’s circumference (1/10 000 000 of the equator-pole distance)
Imagine using nautical kilometers, road kilometers, space kilometers, imperial kilometers, protestant kilometers…
Now please tell me there are no nautical feet, yards, inches and furlongs
No, but there are fathoms and leagues
There is the imperial/customary/international foot defined as 0.3048 m, and the surveyor’s foot defined as 1200/3937 m (aka .304800609601219202438404 m)
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Well, to be fair, there has been, the surveyor’s foot was deprecated in 2023.
I think the most insane combination of units can be found in aviation. They use feet for altitude but nautical miles for distance, then they use knots (nautical miles per hour) for horizontal velocity, but for vertical velocity they use feet per minute.
Just last week I found this unit right here and I still haven’t stopped chuckling
https://en.wikipedia.org/wiki/Foot-candle
Well, and then you need a US customary mass unit when you’re designing the things.
Introduce the slug, not to be confused with a pound-mass (lbm), which is distinct from pound-force (lbf).
And then you can start building inertial moments in slug-ft^2.
The nautical mile comes from the measure of 1 second of arc (°,mn,s) of longitude over the earth. Hence British nautical and French nautical mile conversion were slightly different as they were not defined at the same latitude.
I did not know their origin, that’s hilarious.
That explains why the people who designed the meter found it logical for it to represent a portion of Earth’s circumference (1/10 000 000 of the equator-pole distance)
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