Physics units

DarK SagE

Golden Member
Oct 9, 1999
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My physics teacher is making us do some silly extra credit project on physics units. He wants us to find some interesting unit (something that's not "vanila" like meter or newton) and creat a posterboard about it. Can you guys sugest an interesting unit to write about?
 

RedFox1

Senior member
Aug 22, 2000
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In terms of data, 1 unit is a bit, 4 is a nibble and 8 is a byte. Kinda funny. Doesn't have much to do with physics I guess, though.

-RedFox1
 

rahvin

Elite Member
Oct 10, 1999
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oh come on, all the interesting ones are the english units.

Try horsepower, furlong, inch, chain, slug, ^F, mile, acre, but by far the best english measurement is the width between railroad tracks (the gauge). Bonus points to anyone that can explain why Railroad tracks are 4' 8 1/2" apart.
 

Ladi

Platinum Member
Apr 21, 2000
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I can't resist...

railroad tracks are often 4'8.5" apart because that was the ideal wheelbase for horse-drawn carts during the Roman Empire, when many early European roads were built. these roads were often maintained/expanded upon for future transportation efforts, including the railroad.

HOWEVER, railroad tracks in america didn't always follow this standard and in fact, several different gauges existed in different regions because each railroad company generally had a monopoly to operate in its specific area and built its own tracks/railroad cars (no standardization existed). This led to high costs of shipping (every time you had to cross one of these artificial borders, somebody had to physically move all of your goods from one railroad car to another that could run on this other company's proprietary gauge. There's a series of inventions that you can look up in the patent archives that deal with cars that were specially designed to use different gauged tracks with wide wheels or complex wheelbase/axle mechanisms. Standardization of american railroad gauges was a result of smaller railroad companies merging/being bought out and economic pressure (from people who needed goods shipped at cheaper prices and in some areas, from canals providing much cheaper/faster shipping), as well as other reasons.

My academic concentration is technology/science history in america :)

~Ladi
 

Bignate603

Lifer
Sep 5, 2000
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Ladi, you forgot one part of the story... the space shuttle's boosters were assembled far away from florida where they would be launched and because of this they had to go through a railroad tunnel not a huge amount wider than the track. They wanted to make the booster wider but couldn't because the tunnel wasn't large enough. Now the gauge of the track was based off the size of a wagon, basically the size of two horse's rear's plus a bit for some extra room. Because the tunnel was based off this, the most advanced transportation device was limited.

Next time you see some really odd standard when you're working think before you say "What horse's ass decided this?!?" because that horse's ass my have well been what determined it.
 

rahvin

Elite Member
Oct 10, 1999
8,475
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<<If I remember correctly, it's because that's the width between old wagon wheels.>>

Correct.

<<railroad tracks are often 4'8.5&quot; apart because that was the ideal wheelbase for horse-drawn carts during the Roman Empire, when many early European roads were built. these roads were often maintained/expanded upon for future transportation efforts, including the railroad.>>

Ah! More detail...

<<Now the gauge of the track was based off the size of a wagon, basically the size of two horse's rear's plus a bit for some extra room.>>

Oh and there is the cincher. So in summary people. The width of the modern railroad track was influenced and is a direct result of the width of two Roman war horse's asses. So as stated previously, whenever you wonder why something is designed/built the way it is, consider the Roman horses and the width of their asses.

 

HomerSapien

Golden Member
Jul 19, 2000
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do one explaining which greek letters are used for what. example alpha = angular acceleration. omega = angular velocity. delta = change. and so on.
 

rahvin

Elite Member
Oct 10, 1999
8,475
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<<do one explaining which greek letters are used for what. example alpha = angular acceleration. omega = angular velocity. delta = change. and so on.>>

There is no hard definition of the greek letters, depends on the discipline.
 

Hanpan

Diamond Member
Aug 17, 2000
4,812
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Sorry it's been a while. I'v eonly been studying straight math lately ;)

Sorry. Magnetic Flux Density.
Now who can tell me what magnetic flux is ;)
 

Shalmanese

Platinum Member
Sep 29, 2000
2,157
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fixed link from denali:

link

there was a really old one which was defined as the area of field the average horse could plough in the average day, though that was pretty funny