willard 0 #1 February 8, 2007 "In the SI system of units, mass is measured in kilograms (kg). Many other units of mass are also employed, such as: grams (g), tonnes, pounds, ounces, long and short tons, quintals, slugs, atomic mass units, Planck masses, solar masses, and eV/c2." This was pulled from their definition of mass. Pounds are units of weight, not mass. Same with grams and tons. Quote Share this post Link to post Share on other sites
sundevil777 102 #2 February 8, 2007 The kilogram is a unit of mass: http://www.physics.nist.gov/cuu/Units/units.html The pound is not a unit of mass, but the kilogram is.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
livendive 8 #3 February 8, 2007 And gay means happy, not homosexual dammit! Blues, Dave"I AM A PROFESSIONAL EXTREME ATHLETE!" (drink Mountain Dew) Quote Share this post Link to post Share on other sites
willard 0 #4 February 8, 2007 QuoteThe kilogram is a unit of mass: http://www.physics.nist.gov/cuu/Units/units.html The pound is not a unit of mass, but the kilogram is. Yep. Kilos*9.8=Newtons, a unit of weight. Slugs*32.2=pounds. It's a fairly simple concept, so if the eds missed that it makes me wonder what else they slipped up on. Quote Share this post Link to post Share on other sites
sundevil777 102 #5 February 8, 2007 Newtons is a unit of force, not weight. Same with slugs.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
kallend 2,150 #6 February 8, 2007 Quote"In the SI system of units, mass is measured in kilograms (kg). Many other units of mass are also employed, such as: grams (g), tonnes, pounds, ounces, long and short tons, quintals, slugs, atomic mass units, Planck masses, solar masses, and eV/c2." This was pulled from their definition of mass. Pounds are units of weight, not mass. Same with grams and tons. The gram most IS certainly a unit of mass, as is the pound in the foot-pound-second system of units, in which the poundal is the unit of force (and weight). In fact every one of the units mentioned by Wikipedia may be used as a mass unit in a physically consistent system. So there.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
kallend 2,150 #7 February 8, 2007 QuoteNewtons is a unit of force, not weight. Same with slugs. Weight and force are dimensionally the same. Slugs most definitely ARE mass units. 1 slug = 15kg approximately. If you don't believe me, ask a physics professor.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
kallend 2,150 #8 February 8, 2007 Quote Slugs*32.2=pounds. So if the dimensionality of the slug is [mass], and the dimensionality on each side of the equals sign MUST be the same, what does that make the dimensionality of the pound according to your equation above? I don't think you know what you are writing about. If you don't believe me, ask a physics professor.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
willard 0 #9 February 8, 2007 QuoteQuote"In the SI system of units, mass is measured in kilograms (kg). Many other units of mass are also employed, such as: grams (g), tonnes, pounds, ounces, long and short tons, quintals, slugs, atomic mass units, Planck masses, solar masses, and eV/c2." This was pulled from their definition of mass. Pounds are units of weight, not mass. Same with grams and tons. The gram most IS certainly a unit of mass, as is the pound in the foot-pound-second system of units, in which the poundal is the unit of force (and weight). In fact every one of the units mentioned by Wikipedia may be used as a mass unit in a physically consistent system. So there. The passage I quoted from Wikipedia contained both units of mass and units of weight. I slipped and included grams as weight, they are indeed mass. Units of weight are dependent upon gravity to give them their values, units of mass are not. One kilo is one kilo regardless of whether it is on the ground or in space. That one kilo weighs/exerts one Newton at 9.8 m/s^2 gravity. "Mass is an inherent property of an object and is independent of the subject's surroundings and of the method used to measure it. Also, mass is a scalar quantity and thus obeys the rules of ordinary arithmetic...... Mass should not be confused with weight. Mass and weight are two different quantities. The weight of an object is equal to the magnitude of the gravitational force exerted on the object and varies with location." Physics for Scientists and Engineers, 6th Edition Serway & Jewett BTW, I didn't need to consult an physics professor. It was a physics/engineering professor who pointed out the boo-boo in Wikipedia to our class. Quote Share this post Link to post Share on other sites
dorbie 0 #10 February 8, 2007 Quote Yep. Kilos*9.8=Newtons, a unit of weight. It's a fairly simple concept, so if the eds missed that it makes me wonder what else they slipped up on. You have omitted the units for one of your terms. Kilos * 9.8 what? That should be 9.8 N/Kg, hence the result is in Newtons, a unit of force, and very different from Kg a unit of mass. Pot calling the kettle black if you ask me. Quote Share this post Link to post Share on other sites
sundevil777 102 #11 February 8, 2007 QuoteQuoteNewtons is a unit of force, not weight. Same with slugs. Weight and force are dimensionally the same. Slugs most definitely ARE mass units. 1 slug = 15kg approximately. If you don't believe me, ask a physics professor. Ooops, I knew that, just a brain fart.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
willard 0 #12 February 8, 2007 slug is a unit of mass pound is unit of weight 32.2 is gravity at sea level One slug (mass) times 32.2 feet per second per second (gravity) equals one pound (weight) What is inaccurrate about that? Quote Share this post Link to post Share on other sites
kallend 2,150 #13 February 8, 2007 Quoteslug is a unit of mass pound is unit of weight 32.2 is gravity at sea level One slug (mass) times 32.2 feet per second per second (gravity) equals one pound (weight) What is inaccurrate about that? Nothing in the foot-slug-second system However, in the EQUALLY VALID foot-pound-second system, the pound is the mass unit and the poundal is the force and weight unit. See THIS, and tell your physics professor he needs to study more. If you don't believe me, ask a physics professor... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
jakee 1,596 #14 February 8, 2007 QuoteWhat is inaccurrate about that? Hehe, that's funny.Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites
willard 0 #15 February 8, 2007 QuoteQuoteslug is a unit of mass pound is unit of weight 32.2 is gravity at sea level One slug (mass) times 32.2 feet per second per second (gravity) equals one pound (weight) What is inaccurrate about that? Nothing in the foot-slug-second system However, in the EQUALLY VALID foot-pound-second system, the pound is the mass unit and the poundal is the force and weight unit. See THIS, and tell your physics professor he needs to study more. If you don't believe me, ask a physics professor Do you really expect most people who read that entry in Wikipedia to realize that there is such a system as the poundal system? You know it, I know it, my Prof knows it. But I'll betcha Mary Jane Rottencrotch down the street doesn't know it. Sure, you can pick nits and prove that technically I am wrong, but in the real world most people don't care much for nits. (BTW, pound was a unit of weight long before it was a unit of mass) As for my Professor, I would love to someday be so overwhelmingly intelligent and superior to all that I could actually tell someone of his accomplishments that they don't know what they are talking about. Quote Share this post Link to post Share on other sites
jakee 1,596 #16 February 8, 2007 QuoteDo you really expect most people who read that entry in Wikipedia to realize that there is such a system as the poundal system? You know it, I know it, my Prof knows it. But I'll betcha Mary Jane Rottencrotch down the street doesn't know it. So... Wikipedia should only contain information that everybody knows already? QuoteSure, you can pick nits and prove that technically I am wrong, but in the real world most people don't care much for nits. Well shit Copernicus, sure you could nitpick and say the earth spins round the sun - but in the real world everyone knows it's what goes up and down every day. Why should Wikipedia be forced to cater to the lowest common denominator?Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites
BIGUN 1,488 #17 February 8, 2007 If you don't believe me, ask a THE physics professorNobody has time to listen; because they're desperately chasing the need of being heard. Quote Share this post Link to post Share on other sites
willard 0 #18 February 8, 2007 QuoteSo... Wikipedia should only contain information that everybody knows already? Nope. Point I was trying to make, that you obviously didn't get, was that people who already know there is a difference between pound-force and pound-mass will know that there is a mass unit called a pound, but those who do not know of the difference will come away from reading that entry thinking that pounds are always units of mass. QuoteWell shit Copernicus, sure you could nitpick and say the earth spins round the sun - but in the real world everyone knows it's what goes up and down every day. No, you couldn't nitpick about the relation of the earth and sun and prove it to be opposite what we already know and have proven to be fact. QuoteWhy should Wikipedia be forced to cater to the lowest common denominator? Because that seems to be their biggest fan base. There is a reason every college class I have been in that required a written project specifically stated that Wikipedia is not a reliable enough reference to be included in a bibliography. Quote Share this post Link to post Share on other sites
dorbie 0 #19 February 8, 2007 Quote Nope. Point I was trying to make, that you obviously didn't get, was that people who already know there is a difference between pound-force and pound-mass will know that there is a mass unit called a pound, but those who do not know of the difference will come away from reading that entry thinking that pounds are always units of mass. Is that why you said, "Pounds are units of weight, not mass. Same with grams and tons"? The attached image should explain things. Quote Share this post Link to post Share on other sites
willard 0 #20 February 8, 2007 Nice shovel. What's the implication? Quote Share this post Link to post Share on other sites
champu 1 #22 February 8, 2007 On spacecraft, most components have specified weights measured in pounds... ...figure that one out. Quote Share this post Link to post Share on other sites
willard 0 #23 February 8, 2007 I already aknowledged that I slipped and included grams as weight when I shouldn't have. Since a ton is 2000 pounds, it also is a measure of weight....in the most commonly used sense If I said my car is 3000 pounds, you wouldn't say that statement didn't make sense because you assume, like 99% of the population, that I am talking about a unit of weight...a measurement of force. If you said, "Yeah, but what does it weigh?" I would probably say something smartassed like,"I don't know. That depends on where you're at." Both of us would be technically correct, yet both remarks were pointless. Some people have to go one step beyond and bring up an obscure definition that most people have never heard of. Yes, I have done calculations using poundals, but not very often. Almost always we are using kilos, newtons, kN, etc. Thanks for the shovel, but I really don't need one. I live in an apartment and the owners don't take kindly to me digging holes in the floor. Quote Share this post Link to post Share on other sites
willard 0 #24 February 8, 2007 NASA uses pounds as both a unit of mass and a unit of weight. Same with Kilograms. Quote Share this post Link to post Share on other sites
champu 1 #25 February 8, 2007 QuoteNASA uses pounds as both a unit of mass and a unit of weight. Same with Kilograms. Is NASA an acceptable reference for scientific information? Quote Share this post Link to post Share on other sites
