I suppose you can't really blame the unit. it was perfectly ok until that git Newton came along with his three laws.
Pound/poundal Slug/pound
Take yer pick, and Mars is the orange one fourth from the sun :-)
Mark Rand RTFM
I suppose you can't really blame the unit. it was perfectly ok until that git Newton came along with his three laws.
Pound/poundal Slug/pound
Take yer pick, and Mars is the orange one fourth from the sun :-)
Mark Rand RTFM
Only in the FPS system, in the US Customary System the pound is a unit of mass. See my recent post re the origin of the FPS system and the slug. It seems the poundal existed as a unit of force before the slug was introduced as a unit of mass. I think I'd be less confused if whoever introduced the FPS stuck with the pound for mass and the poundal for force.
Ned Simmons
Don't they also consider the "pound (force)" a unit of force?
R, Tom Q.
Joe, and Don, I am going to put together what I want to have, with clamps, will post a picture. I will definitely test them to at least 2 tons.
i
Sorry, I should've avoided abbreviations; lbf = pound force.
Ned Simmons
Whoops, I was I little too quick with my reply.
I'm guessing that the "lbf" in your post is the same as the "pound (force)" in my reply.
As Roseanne Roseannadanna used to say, "Never mind".
R, Tom Q.
ClapClapClap!
Nick
Yabbut you chaps serve short pints and short tons as well :-)
Mark Rand RTFM
Historically, the pound is a unit of weight, which is the same thing as a unit of force. Needing to join the modern world and recognizing that gravity varies from place to place, the UK and the US now officially recognize the pound as a unit of mass, defined, ultimately, in terms of the kilogram.
Regarding the standard values of gravity used to determine the pound of force, and the standard conversion for the pound as a unit of mass, consult a textbook.
So, yes, "pound" can mean either. Yes, it is ambiguous. This is one good reason to stick to the metric system when you're doing anything serious.
In scientific work that still uses the old English system -- in whatever obscure corner of the world that may be -- the unit used for force can be the "poundal," as well as the "pound-force." A poundal, I see after looking it up, is 1/32 of a pound-force. I don't know if that's exact or approximate.
Except for measurement of length, in which it doesn't make a hell of a lot of difference, stick to metrics for serious work involving mass, force, etc., if at all possible.
-- Ed Huntress
Ok, teach. I've got it.
1) The unit of Mass is the hour, unless it is High Mass, in which case I always fell asleep before I knew how long it really was.2) The unit of force is the same thing as the threat of detention. They can be converted to each other by a factor that depends on how nice it is outdoors.
3) One pound is worth about $1.91, although that could change tomorrow.4) Alum or diatomaceous earth are good treatments for slugs. If you accelerate them with a slingshot, they make a hell of a splat when they hit the wall.
Can I go home now?
-- Ed Huntress
So I found out. I was called on it in another newsgroup a few years ago when I stated that it was a unit of force or weight.
~ 1/32 of a pound would make sense, given the (average) gravitational constant.
Sure. Except 6" doesn't sound as impressive as "over 150 millimeters".
R, Tom Q.
"Strictly speaking" it wasent a unit of mass when I took Physics at PSU in 1954. It was a Force. As I remember mass in the "english" system was Slug. ...lew...
Ed, acording to my old college physics book (Sears and Zemansky) which I happen to have on my lap at the moment, Page 76, the unit of mass in the "British engineering system of units" is the Slug. lb/(ft/sec sq)
I had thought better of you. :-) ...lew...
Mark Rand wrote
A-Men Mark These folks that sound like they never had a physics course in their life. It's a wonder they can do trig. (If they can) ...lew...
Ah, Lew, you're taking this all too seriously. Anything called a "slug" can't be serious. Neither is an "erg" serious.
As for "poundal," they should have quit while they were ahead. It sounds like something you're supposed to do with a suppository. d8-)
A "Newton" should be the name for an apple. A "Pascal" should be a wager. "Moles" should stay in the ground, where they belong.
And how about those prefixes! How could anyone take a "yotta" (10^24) seriously? "Man, that's a yotta sand on that beach." How about a "yocto" (10^-24)? Or a "zepto" (10^-21)? Anybody for a "femto" (10^-15)? It sounds like the Marx brothers' country cousins.
It's all a big joke. Somebody up there is laughing at us.
-- Ed Huntress
You have to remember that most leading edge physics is done by long haired pimply faced youths who are really more interested in wimmin and beer, the same as most pimply faced youths :-)
Mark Rand RTFM
The important qualifier there is "in the "British engineering system of units", - not so in the US customary system. I bet that's one of those physics books that says there's no such thing as centrifugal force.
Ned Simmons
If that counts:
or this:
lb and slug is mass, lbf is force (and lbf is pound-FORCE).
I have _never_ seen used the "kgf" they mention on the forces-page. Those historic units are such a mess (mass weight force) and commonly completely misunderstood or simplyfied (I also often say weight and mean mass) that it is best to kick them and go strictly SI.
Yea, I know the metric/decimal imperial/dozend battle and don't intend do start a new one.
BTW: lb is pound, but how does the abbrev. come? I cant see the letter "l" and "b" in "pound"?
Nick
Trouble with moles? Call AVagadro 6 0221, Extension 1023
Its all that tea they drink.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.