When it comes to insulation temperature rating, why do we use celsius?

winnie said:
If you apply a force of one pound pound over a distance of 1 foot, you've done one foot pound of work.

If you apply a force of one pound on a 1 foot lever arm, you apply one foot pound of torque.

Same units, different concept (energy vs torque). If both are being used in a single context, it is common to call one a pound foot and the other a foot pound, but I don't think there is any real standard about which is torque and which is work. I tend to use pound foot to mean torque and foot pound to mean energy.

In SI, the unit of energy is the Joule, and the unit of torque is the Newton meter. But a force of 1 Newton applied over a distance of 1 meter is 1 Joule of work.

An alternative argument: energy is force (dot) distance, torque is force (cross) distance. The dot product and the cross product are different things, so while both are pound (something) feet, since we don't actually say the (something), the difference is lost in the word foot pound (and equally lost in Newton meter), but they really are different units because of the (something) that is lost.

-Jonathan
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It's interesting to think about in terms of units with dimensions. Since energy is force x distance, and energy is also torque x angle, torque MUST have the same units as energy BECAUSE angle is dimensionless.🤯
 
And today we will drop into the local. My wife will have a 250 ml white, I have a pint of Scrumpy..........
 
16 ounces to the pound made sense. As long as you can agree on what a pound is you can divide it into ounces with a double pan balance without having to refer to any other standard weights.
 
ggunn said:
16 ounces to the pound made sense. As long as you can agree on what a pound is you can divide it into ounces with a double pan balance without having to refer to any other standard weights.
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"A pint's a pound the world around" is actually pretty close to true. A fluid ounce of water at STP is an ounce of mass. Under the conditions in which the imperial system was invented, it wasn't all that crazy to name the volume unit after the mass unit, or vice versa.
 
ggunn said:
Same here. It's frustrating to have to use Imperial units in AutoCAD when I have to divide up a rooftop measurement into five equal segments and the length is something like 147' 9-7/16" and express the result in Imperial units. I can do it but I am grinding my teeth the whole time. Engineers and architects are at loggerheads. :D
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Or adding up imperial measurements on a set of plans to layout a rough in, 7 rooms away from the control point.
 
CoolWill said:
"A pint's a pound the world around" is actually pretty close to true. A fluid ounce of water at STP is an ounce of mass. Under the conditions in which the imperial system was invented, it wasn't all that crazy to name the volume unit after the mass unit, or vice versa.
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A pint (UK) is 586 ml and, as a rule, the pub uses pint glasses. Even in Scotland..................)
 
CoolWill said:
"A pint's a pound the world around" is actually pretty close to true. A fluid ounce of water at STP is an ounce of mass. Under the conditions in which the imperial system was invented, it wasn't all that crazy to name the volume unit after the mass unit, or vice versa.
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If it were, we'd have the same number of grams in a pound, as we have milliliters in a pint. We do not.

If it were my choice, I would've assigned 480 as the number for both conversions.
 
Carultch said:
If it were, we'd have the same number of grams in a pound, as we have milliliters in a pint. We do not.

If it were my choice, I would've assigned 480 as the number for both conversions.
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I said pretty close to true, not exactly precisely true.
 
Besoeker3 said:
Yes, I agree Mr Mod., I remember those units from school physics. - I was about sixteen then. people But then I got in to my degree and it was all SI units. That said, many here still use Imperial, units especially older people.
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Just how old are they if you are one of the young ones? :cool:
 
Carultch said:
18 inches. It's based on the distance from elbow to fingertip, of a 6 ft tall person.
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Probably the last King that designated his dimensions as being the official unit.

The length of his foot is also likely what is still one foot today.
 
kwired said:
Probably the last King that designated his dimensions as being the official unit.

The length of his foot is also likely what is still one foot today.
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The history of units of measure is intimately intertwined with politics. Fortunately political history so that we don't run afoul of forum rules discussing it :)

Apparently Jefferson and Adams were early proponents of using the metric system, but it took until 1866 to officially adopt metric units as _allowed_ for commerce in the US. The law in 1866 set approximate conversions, so the meter was approximately 39.37 inches long.

Sometime in the late 1800's, the metric units were taken as the standard, with customary units defined in terms of the basic metric units. The yard was standardized as exactly 3600/3937 meter (making the meter 39.37" exactly, by definition)

In 1959 the standards were changed to make the inch _exactly_ 2.54 cm, redefining things by 0.0002 % Thus begat the difference between the 'foot' (or 'international foot') and the 'survey foot', two different units of length. The survey foot was used for geodetic surveys, the only situation (at the time) were measurements were accurate enough that the difference mattered.

Still love me my SI, still ornery enough to push back whenever someone tries to force its use.

-Jonathan
 
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