i'm usually pretty good at math, but i'm stumped

[KeepItSimpleStupid]

Ratch:

I know. It was literally drilled into my head early using just that analogy. I have no issues with it.

KISS

 

[meowth08]

E=.5*mass*velocity^2

E=.5*[(lbf*seconds^2)/ft]*[(ft^2)/seconds^2]

Note:1 pound force=32.174 pound mass

 

[Ratchit]

meowth08,

E=.5*mass*velocity^2

Yes, everyone who has studied physics knows this. And your point is?

E=.5*[(lbf*seconds^2)/ft]*[(ft^2)/seconds^2]

Yes, what are you trying to say?

Note:1 pound force=32.174 pound mass

No it does not. You cannot equate force to mass. At standard Earth gravity, a one pound mass will exert a one pound force. At Earth gravity, a 32 pound mass will exert 32 pounds of force (lbf).

Ratch

 

[unclejed613]

so.... 1 slug moving 1fps=1ft-lb, correct?

 

[Ratchit]

unclejed613,

so.... 1 slug moving 1fps=1ft-lb, correct?

Nope. E = ½mv² = ½ ft-lbf

Ratch

 

[BrownOut]

One slug would weigh 32 pounds near the Earth's surface. https://en.wikipedia.org/wiki/Slug_(mass) An object weighing 1 pound would have a mass of 1/32 slugs. One slug travelling at 1foot/sec is the same energy as 1/32 slugs raised to a height if 1/2 foot.

 

[unclejed613]

i grew up with both the "american" english system and the SI system.... now i begin to see why the english system is so #$^#&$ confusing... it would have been easier to convert to SI, do the calculation and convert back to english.

 

[duffy]

Best thing I can say about the imperial system is it helps kids learn fractions and division - like knowing a 3/8" socket is smaller than a 1/2", and that a 9/16" is bigger, 3/4 of a cup + 1/4 = 1 cup, 4 oz = 4/16ths lb = 1 quarter-pounder with cheese, etc.

I have to use imperial on engineering drawings - but when I'm doing anything that looks like science, I use metric.

 

[Ratchit]

Uncle Jed,

i grew up with both the "american" english system and the SI system.... now i begin to see why the english system is so #$^#&$ confusing... it would have been easier to convert to SI, do the calculation and convert back to english.

You have two things going against you. First, the English system in not decimalized. Second, you are not very familiar with the units. By the way, what do you have against capital letters?

Ratch

 

[BrownOut]

If one wants to be versatile enough to work ( or play ) in the various technical fields, he should learn to be conversant in the major units systems. That’s the point I wanted to make earlier when someone was complaining he wasn’t taught the imperial system. Hell, neither was I, but since I like performance automotive tuning, I had to learn to think in those units. No point in complaining what you were taught, because you have to learn to teach yourself. Living in this world requires it.