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Reposted because of server error, possible but unlikely that some get
multiple copies. wrote: I am 240 pounds 'mass' on earth. That's a fact. I am 240 pounds 'mass' on moon. That's a weird assertion! You've got me totally buffaloed now. I can't imagine what your problem is. Sure, mass is an ambiguous word, with several different meanings. But there is only one of its meanings that is normally used with numbers to express a measurement of its magnitude. If that assertion is true, who changed the density of the moon?? What in the world would the density of the moon have to do with your mass? It would be more understandable if you were having a hard time understanding the normal definitions for this particular context of the ambiguous word 'weight,' as it is quite properly and legitimately used for body weight of humans in medicine (including space medicine by NASA astronauts and doctors), and in sports, the normal reasons we weigh ourselves, and in the science of anthropology as well. Or as the word 'weight' is also used in zoology and veterinary medicine and paleontology for the weight of other animals as well as humans. Now certainly, in any of these contexts, this quantity will sometimes be referred to as 'mass' as well; that is also quite proper and legitimate. My 'weight' is 230 pounds on earth. That's a fact. My 'weight' would be 230 pounds on the earth's moon. That's also a fact. Let's review what I've already posted in other messages in this thread, from ASTM . . . thus, when one speaks of a person's weight, the quantity referred to is mass. . . . and from NIST Thus the SI unit of the quantity weight used in this sense is the kilogram (kg) and the verb "to weigh" means "to determine the mass of" or "to have a mass of". Examples: the child's weight is 23 kg You know damn well that those kilograms are used for body weight all around the world, including most hospitals in the United States. They are indeed the proper SI units for this weight (which, as I pointed out above, is also sometimes called "mass" instead). Furthermore, as you've already seen many times over in the past few days, pounds are by definition exactly 0.45359237 kg. http://www.ngs.noaa.gov/PUBS_LIB/Fed...doc59-5442.pdf THE REAL WORLD, AND THE REAL MOON Now let's look at something different, not dealing with imaginary transportations of you or me to the moon, but with the real world, and the real moon. What do you suppose it means when NASA tells us that the weight of the Apollo 11 Lunar Module was "10,776.6 lbs" at the time of liftoff? What ... Whoops, just about forgot where I was and got ahead of myself, forgetting that I need to slowly spell out what might be obvious to people in other newsgroups. The Lunar Module at liftoff, of course, was in actual fact located right ON THE MOON. Now, what do you suppose those pounds are? If you really have no idea how big the Lunar Module is and what its weight might be on the moon, here's a big hint. NASA also tells us that the same Lunar Module at the time of docking had a weight of 5738.0 lb. Selected Mission Weights http://history.nasa.gov/SP-4029/Apol...on_Weights.htm Where was this LM at the time of docking? That's when it caught up with the command module, where Commander Collins was at that time "weightless" in an entirely different definition of the word weight, in free-fall orbit around the moon. But not only was he not weightless in the definition being used by NASA for this LM weight, though he also was far from weightless in the definition of "weight" as a force as used by Sears and Zemansky, from whom you claim to have learned your physics. Much less in terms of force units than he would have been on Earth (about a tenth as much, only an order of magnitude guess), of course, but far from zero, in the Sears and Zemansky definition of weight. [Sears and Zemansky, 1970 page 61] 5.5 MASS AND WEIGHT The weight of a body can now be defined more generally than in the preceding chapters as the resultant gravitational force exerted on the body by all other bodies in the universe. . . . There is no general agreement among physicists as to the precise definition of "weight." Some prefer to use this term for a quantity we shall define later and call the "apparent weight" or "relative weight." In the absence of a generally accepted definition we shall continue to use the term as defined above. The NASA site discussed above, of course, is not some aberrant web page. Nor is it some alteration of the units by the NASA public affairs office--this is straight from the scientists and engineers. This is indeed normal NASA usage, to call this "weight." It is also normal NASA usage of the units "pounds." We even know that this is exactly the term under which it was programmed into their onboard computers, and the units used there as well, because we have dialogs between Ground Control and the astronauts in which they are reading out these figures for something called "weight" on both ends of the conversation, and those weights are in pounds mass. You also routinely see the same usage of the word weight when NASA talks about the weight of the space shuttles or the weight of components of the Space Station, or the weight of the spinning satellite some spacewalkers wrestled into submission a few years ago.. As an aside, what do you think: Will NASA ever learn the lesson of the Mars Climate Orbiter, and quite using pounds? -- Gene Nygaard At the present time, however, the metrical system is the only system known that has the ghost of a chance of being adopted universally by the world. -- Alexander Graham Bell,1906 |
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Roger Halstead wrote in message . ..
On Sat, 27 Sep 2003 11:48:24 GMT, Dave Shrader wrote: I am 240 pounds 'mass' on earth. That's a fact. No, in the US system of measurement your mass is measured in slugs. your weigh is measured in pounds and is 240# on earth In the metric system mass is in kg. Again the metric system is easier. 240#=109.091 kg If you expect to sound like you have some expertise in this area, I suggest you study up on precision, on significant digits and the like. You can't start with a mass with only 2 or 3 at the most significant digits, and get a conversion accurate to 6 significant digits. Furthermore, if he were 240.000 lb, then he would be 108.862 kg, not 109.091 kg. You also cannot use a conversion factor with only 2 or 3 significant digits, and get a result with six significant digits (you used 1 kg = 2.2 lb, whereas the actual definition of a pound is exactly 0.45359237 kg). I am 240 pounds 'mass' on moon. That's a weird assertion! Your mass is still the same (109.091 kg), but your weight is considerably less on the moon. His mass is still the same, 240 lb, is every bit as true. What's this bull**** about mixing together pounds and kilograms in a totally confusing and stupid system of units? After all, your claim above was that "in the US system of measurement your mass is measured in slugs" so why aren't you using these units? Yes, if his mass is 240 lb, you could also say that his mass is 7.5 slugs. But by the same token, you could use one of the old non-SI metric systems, and say that his mass is 11.1 hyls, in the system in which the base units are the meter for length, the kilogram for force, and the second for time. But the existence of the hyl does not prove that kilograms are not units of mass. By the same token, the existence of the slug does not prove that pounds are not units of mass. Each of those units, the slug and the hyl (aka the metric slug), exist in only one particular subset of units, a subset which forms a coherent system of units like SI, in which there is only one unit for each different quantity and that unit is a unitary combination of the base units. The only system which uses slugs is normally identified as the English (or British, this identifier being a matter of history and derivation), or the U.S. (because it is also used here) "gravitational foot-pound-second system of units." Your characterization of it as "the U.S. system" is vague and misleading, overly broad. The only system which has slugs excludes many of the units used in the United States, such as pints and gallons and bushels and horsepower and Btu and miles and ounces and psi. If that assertion is true, who changed the density of the moon?? It has nothing to do with the assertion, but the mass of the moon is less than the mass of the earth. The mass of the Earth is in fact 81.3 times that of the earth's moon, and you are right, it has absolutely nothing to do with what Dave Shrader was talking about. The mass of you and the earth sets what you weight on earth. Your mass and the mass of the moon set what you weigh on the moon. The No. Even accepting that you are using a force definition of the ambiguous word weight (IOW, a definition nonstandard for the context of body weight), there is one other factor that is also especially important. After all, remember that I told you above that the mass of the Earth is 81.3 times the mass of the moon. Do you think that the force due to gravity that an object exerts on Earth will be 81.3 times the force that the same object would exert on the moon? What do you suppose that other important factor might be (hint--while the force varies only linearly with mass, it varies in inverse proportion to the square of this other factor). mass of the moon is much less than that of earth so you weight much less on the moon. -- Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ "It's not the things you don't know what gets you into trouble. "It's the things you do know that just ain't so." Will Rogers |
Gene Nygaard wrote:
"You are talking about something different from mass." Yes. An orbiting astronaut may be weightless due to a particular balance of forces, but he has mass and inertia. We have weight and force. Either weight or force may be expressed in pounds or kilograms. The conversion number I remember and use is: 2.2 pounds equal 1 kilogram. The dictionary says the kilogram is a unit of mass, since a mass can conveniently be accurately represented by an object. That particular object is a cylinder of platinum-iridium alloy, called the international prototype kilogram. This object is preserved in a vault at Sevres, France. Work may be meaasured as force times distance or as pounds times feet. Power is work per unit time. Power may be expressed as foot-pounds per minute. James Watt`s horse was said capable of working at a rate of 33,000 foot-pounds per minute. I calculate that as 250 kilogram-feet per second or 76.2 kilogram-meters per second. Best regards, Richard Harrison, KB5WZI |
On Fri, 26 Sep 2003 22:20:17 GMT, Richard Clark
wrote: On Fri, 26 Sep 2003 20:45:27 GMT, Gene Nygaard wrote: Not only did I prove Mr. Metrologist wrong, but I also proved that he has no integrity. Hi Gene, And yet this does not seem to satisfy you. ;-) No doubt this is product of an insecure basis in logic that is more heartfelt than intuitive (despite the cut-and-paste philosophies). snip As I offered elsewhere; there are many in my fan club who's minds I cannot change. For such trivial matters as yours, I am afraid you have to go to the end of that line, and leave room for others of substance ahead of you. We've already heard the same lame excuse three times before. Translation (from the point of view of Mr. Metrologist, aka R. Clark): I already wasted three hours searching through the NIST web site for a definition of a pound, and I couldn't find one either as a unit of force or as a unit of mass. So I didn't figure that some whippersnapper who just popped into this thread would be able to find any official definition of the pound as a unit of mass there. Okay, so he proved me wrong about pounds as units of mass. But I'll be damned if he's going to get me admit that there isn't any official definition of a pound force on NIST's pages. end of translation There, I told them anyway. BTW, though I can't find an "official" definition of a pound force on NIST's pages, I can find a conditional one, with a big "if" indicating fairly clearly that the pound force has never been officially defined. Can anyone else even find that one? Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ |
On Sun, 28 Sep 2003 13:44:48 GMT, Gene Nygaard
wrote: We've already heard the same lame excuse three times before. Hi Gene, So how deep do I have to plant it before it takes root? ;-) Like this compulsive interest with your fleas, you have written a Gregorian Mass that consists of only one note. To your advantage, if you had transposed "Old MacDonald Had a Farm"; then the monotonic rendition would at least give the appearance of CW. You are dreadfully out of your element here. Given the low intellectual bandwidth offered by your specious claims, I can sit back and enjoy some stylistic variations to exercise my fingers at the keyboard. I especially enjoy your barnyard epithets - such a self fulfilling cliche inspires my anecdotes. Here's another that a liberal education would have exposed you to (if only): 21 Nov. 1667 "On this occasion Dr. Whistler told a pretty story related by Muffett, a good author, of Dr. Cayus that built Key's College: that being very old and lived only at that time upon woman's milk, he, while he fed upon the milk of a angry fretful woman, was so himself; and then being advised to take of a good natured woman, he did become so, beyond the common temper of his age." Oh, if you missed the citation to the quote above, that was again from Samuel Pepys (same day in fact) who, although not trained in the sciences, did learn to respect others of learning and accomplishment. And by the way, that earlier quote: Dr, Wilkins saying that he hath read for him in his church) that is poor and a debauched man, that the College have hired for 20s. to have some of the blood of a Sheep let into his body Contains a Pound reference you obviously missed (from the exchange rate of 20 Shillings). Now, as every good Englishman would have understood back then, this was a conversion. If he held 20 coins they were NOT a Pound which is a single coin. There is an equivalency, but this does not constitute an equality. Pepys could have written 1£ that is shorter, but he did not as it was obviously not what was tendered to the debauched man. Even the debauched man would understand the significance of weight v. mass and how equivalencies of 1pound = umpty-ump grams does not render the term pound as mass, merely an antiquated variant much like 10000 swallows' tongues = 1KG. Shirley you don't consider swallows' tongues as units of mass? Cow tongues (Neat's tongue to the English) perhaps. And this leads us back to the good Dr. Cayus' condition - perhaps you should change your diet. The folks at the end of the line are beginning to complain - could you move back some more? 73's Richard Clark, KB7QHC |
On Sun, 28 Sep 2003 18:04:26 GMT, Richard Clark
wrote: Dr, Wilkins saying that he hath read for him in his church) that is poor and a debauched man, that the College have hired for 20s. to have some of the blood of a Sheep let into his body Contains a Pound reference you obviously missed (from the exchange rate of 20 Shillings). Now, as every good Englishman would have understood back then, this was a conversion. If he held 20 coins they were NOT a Pound which is a single coin. There is an equivalency, but this does not constitute an equality. Pepys could have written 1£ that is shorter, but he did not as it was obviously not what was tendered to the debauched man. Hi All, The application of the monetary unit is not without is antecedents in weight. The ancients, that is the pre-Newtonians, did not comprehend the separable notion of mass from weight as they did not accept the concept of "force" which was largely rejected by scientists of Newton's day. In fact, Newton introduced the notion of forces in his treatise "Opticks." However, to return to the legacy of £. The symbol is drawn from Libra. I have already discussed the operation of the balance scale and its relationship to Libra is evident in the astrological application. Libra (as is the latinate pondo) was the unit of weight (not scientific mass, they had no such distinction) in ancient Rome. I notice that our correspondent who relies on scientific cut-and-paste retorts to dismiss scientific workers; and, as an acknowledged untutored English speaker (several classes notwithstanding) also leverages dictionaries to the same poor quality of transliteration. The OED (which I am sure to get copious and unreliable rebuttal to) offers of "mass" a physics application buried quite deeply within the usage of this word across time (the OED is a dictionary of enumerated usage by time, not by current application). For many hundreds of years, mass merely meant the agglomeration of stuff (it didn't matter what or why). Through the work of Newton's introduction of the concept of force, the term, by OED account, then gained a distinction such that they offer the definition: "6.b. Physics. The quantity of matter which a body contains; in strict use distinct from weight. 1704" This is a pleasurable aside, these side bars of minutia to our usual concerns. A do enjoy the drama queens that our group attracts and the revisionist logic that attends their petty issues. Forgive me Gene, but you don't have much else to offer and you will be gone soon anyway, so go away mad (to invert an old saw). ;-) 73's Richard Clark, KB7QHC |
On Sun, 28 Sep 2003 18:04:26 GMT, Richard Clark
wrote: Given the low intellectual bandwidth offered by your specious claims, Still dreaming that somebody is going to come to your rescue, and show us some NIST web page giving an _official_ definition of a pound as a unit of force, aren't you? Wake up and smell the coffee! It isn't going to happen, for several reasons, including 1. Your research skills are better than those of most others following this thread, and 2. You are better able to distinguish "swallow's tongue" conversion factors from official definitions, and 3. They don't have a reputation to reconstruct, and 4. They don't know people at NIST that they can call on for help in this search for the official definition, and 5. You've got them all convinced that you are an expert in this area, and everyone expects that you could easily prove your point, and 6. A lot of people who know more about this than you do have unsucessfully searched for an official definition, and 7. Dr. Barry Taylor, the NIST expert in this particular field who must be a METROLOGIST if you are a mere capital-M Metrologist, is the one who gives us the conditional definition which is a clear indicator that an official definition does not exist. Face the facts. Hard as it might be to believe (even for me, when I first came to this realization!), THERE IS NO SUCH OFFICIAL DEFINITION OF A POUND FORCE. Nobody has ever gone to the trouble of officially defining these ******* offspring of pounds as units of mass, and nobody will bother doing so in the future. Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ |
On Sun, 28 Sep 2003 22:10:13 GMT, Gene Nygaard
wrote: Wake up and smell the coffee! Hi Gene, You've missed one point (beyond I am not a coffee drinker) to which I can respond: I don't give a damn. :-) Your condescending attitude towards others all convinced that you are an expert is obviously spun from your imagination as absolutely no one here has commented for me, with me, to me, or about me (your QRM hardly allows them that). As for reputation.... You, admittedly, have absolutely no experience in the matter, and this is not rec.sci.amateur.hour. Given your petulance out of the gate discussing the subject, you don't even qualify for honorary troll. You have no style, and the cut-and-paste philosophy runs thick in this group as it is. Yours certainly is no more distinctive, and when it is laid out by the ream like so much textual fertilizer, it won't grow the crops to save the farm. C'mon now Gene, we both know what I have to say on the matter is wholly irrelevant to how you are going to boast about it around town. Sort of like the tailor who wore on his belt "Killed seven with one blow" and was only boasting about flies while gushing it up about giants. Talk about (emphasis on talk) reputations made. ;-) 73's Richard Clark, KB7QHC |
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