Jump to content

Talk:G-force/Archive 1

Page contents not supported in other languages.
From Wikipedia, the free encyclopedia
Archive 1Archive 2Archive 3→Archive 5

contradictions

  • Any exposure to around 100 g or more, even if momentary, is likely to be lethal.
  • Formula One race car driver David Purley survived an estimated 179.8 g in 1977 when he decelerated from 172 km·h−1 (107 mph) to 0 in a distance of 66 cm (26 inches) after his throttle got stuck wide open and he hit a wall.

--

Not necessarily: The first means "Don't try this at home", the second means "but you might get lucky" (roughly). I'd imagine that repeating the experiment is unlikely to be healthy. It is conceivable that restraints reduced the g force somewhat or otherwise made it more likely than usual to be safe. Ealex292 03:56, 1 December 2006 (UTC)

74.129.197.37 (talk)

There are so many factors as to make it nearly impossible to determine the g-force a particular person can survive. Think of the 100g's as an 'LD50' - that is, at least 50% of people would die after being exposed to greater than 100g's. —Preceding unsigned comment added by 74.129.197.37 (talk) 05:59, 15 December 2007 (UTC)

GeForce

People looking for the graphics card GeForce may end up on this page, as gforce redirects here. Just a note JayKeaton 15:01, 29 November 2006 (UTC)

g-force a force?

The article states in the introduction

g-force or g-load is a force-equivalent, equal to 9.80665 N/kg

but N/kg is a unit of acceleration, not of force, so I have to conclude that 1 g = 1 g-force. Is that intended? AxelBoldt 18:09, 19 December 2006 (UTC)

I think "g-force" is a slang term used by people who are somewhat confused about principles of dynamics. I think calling an acceleration a force is ridiculous. RHB100 (talk) 18:03, 28 July 2009 (UTC)

Equivalent versions of Helmert's equation

It might be helpful to note that the version of Helmert's equation in the article is equivalent to the following (discounting rounding errors and expression of lengths in cm instead of meters):

http://lists.nau.edu/cgi-bin/wa?A2=ind0101&L=phys-l&P=39244

g = 980.616 - 2.5928*cos(2*phi) + 0.0069*cos^2(2*phi) - 3.086x10^(-6)*H

where: phi = latitude H = elevation (in cm)

This version is on several web pages and in a CRC Chemistry and Physics Handbook, where it can be difficult to find as noted here:

http://www.lhup.edu/~dsimanek/scenario/labman1/accel!.htm In a CRC handbook like mine, there's no index entry for Helmert's equation. Look up "acceleration due to gravity at any latitude and elevation, equation." It is in the "definitions and formulas" section.

The version above may be calculated more quickly because only one trig value is needed: cos(2*phi). Once that trig value is known, it can be squared for the third term. The version in the article requires calculating two trig values separately: sin(phi) and sin(2*phi).

It may be of interest that there is another, equivalent, version of this formula (with no double-angle trig arguments) which may be obtained by applying trig identities in yet another way. It has the form: g = g_0 * (1 + a * (sin(phi))^2 + b * (sin(phi))^4)

This latter version is not found as frequently on the web, but it is here: http://galitzin.mines.edu/INTROGP/notes_template.jsp?url=GRAV%2FNOTES%2Flcorrect.html&page=Gravity%3A%20Notes%3A%20Latitude%20Variation%20Corrections Ac44ck 07:33, 28 January 2007 (UTC)

Helmert's equation superceded?

There seems to be a more recent (1984) formula for the variation in g with latitude: http://earth-info.nga.mil/GandG/publications/tr8350.2/tr8350.2-a/Chapter%204.pdf

g = 9.7803267714 * (1 + 0.00193185138639 * (sin(L))^2) / sqrt(1 - 0.00669437999013 * (sin(L))^2)

This formula is on page 3 of the pdf file.

Ac44ck 07:38, 28 January 2007 (UTC)

strongest g-forces survived by humans

Probably there's someone with higher g-force survived http://en.wikipedia.org/wiki/Kenny_Brack#Return_to_IRL --84.234.42.68 21:33, 20 June 2007 (UTC)

Proposed changes

To me, the first couple of sections are a bit confusing. I was going to tweak a few things, but in fact ended up effectively rewriting the intro and "Explanation" sections, and incorporating the "Convenient definition" section. Because it's a relatively significant change I feel I should give others the opportunity to comment before applying it to the article. This is what I've got. Matt 02:53, 25 July 2007 (UTC).

g-force (also gee-force, gee-loading) is a measurement of an object's acceleration expressed in gees. The "gee" (pronounced [dʒiː]; symbol g) is a non-SI unit equal to the nominal acceleration due to gravity on Earth at sea level, defined as 9.80665 m/s2, or approximately 32.174 ft/s2. More precisely, g-force measures the difference between the acceleration that an object actually experiences and the acceleration that gravity is trying to impart to it, as explained further below. The symbol g is properly written in lowercase and italic, to distinguish it from the symbol G, the gravitational constant, which is always written in uppercase; and from g, the symbol for gram, which is not italicized.

Although strictly a measurement of acceleration, the term g-force, as its name implies, is commonly understood to refer to the force that an accelerating object "feels", expressed as a multiple of the force that it "feels" when resting stationary on the Earth's surface. The relationship between force and acceleration stems from Newton's second law, F = ma, where F is force, m is mass and a is acceleration.

These so-called "g-forces" are experienced, for example, by fighter jet pilots or riders on a roller coaster, and are caused by changes in speed and direction. For example, on a roller coaster high positive g-forces are experienced on the car's path up the hills, where riders feel as if they weigh more than usual. This is reversed on the car's descent where lower g-forces occur, causing the riders to feel lighter or even weightless.

Because of the potential for confusion about whether g-force measures acceleration or force, the term is considered by some to be a misnomer. Scientific usage prefers explicit reference to either acceleration or force, and use of the appropriate units (in the SI system, metres per second per second for acceleration, and newtons for force).

Calculating g-forces [level 2 heading]

Unlike simple acceleration, g-force is a measure of an object's acceleration relative to the local gravitational acceleration vector, rather than being compared to an inertial reference frame. In other words, it is the (vector) difference between an object's actual acceleration and the acceleration that it would experience if it were falling freely. It is this difference, rather than the actual acceleration of the object, that gives rise to the feeling of force ("apparent weight"), and hence to the feeling of heaviness and lightness in high and low g-force environments. For further details, including examples of conversion between acceleration and apparent weight force, see apparent weight.

In a simplified scenario, where accelerations are assumed to act only downwards (positive) or upwards (negative), calculating this difference simply amounts to subtracting the object's actual acceleration from the gravitational acceleration. For an object on or near the Earth's surface, gravitational acceleration is for practical purposes equal to 1 g. (For more precise measurements, the variation of Earth's gravity with location and altitude must be taken into account.) So, for example:

  • A non-accelerating object experiences a g-force of 1g − 0g, or just 1g ("normal weight").
  • An object in free fall (accelerating downards at 1g) experiences a g-force of 1g − 1g = 0g ("weightless")
  • An object accelerating upwards at 1g experiences a g-force of 1g − (−1g) = 2g ("twice normal weight")
  • An object accelerating downwards at 2g experiences a g-force of 1g − 2g = −1g ("negative g").

More generally, the object's acceleraion may act in any direction (not just vertically), so in a fuller treatement it must be considered as a vector quantity. The "difference" in acceleration that g-force measures is found by vector addition of the opposite of the actual acceleration and the local gravitational acceleration vector (about 1 g downward on or near the Earth's surface).

In cases when the magnitude of the acceleration is relatively large compared to 1 g, and/or is more-or-less horizontal, the effect of the Earth's gravity is sometimes ignored in everyday treatments. For example, if a person in an car accident decelerates from 30 m/s to rest in 0.2 seconds, then its deceleration is 150 m/s2, so one might say that it experiences a g-force of about 150/9.8 g, or about 15.3 g. Strictly speaking, due to the vector addition of the gravitational acceleration, the true g-force has a slightly larger magnitude and is pointing slightly downwards (intuitively this is because the car is already experiencing 1 g just by sitting on the road).

Comments on proposed changes

  • I don't think example calculations should be included. Explained some but no great detail. It looks like a tutorial thing to me. What about the human tolerance & experience stuff? Do you want to get rid of that? I wouldn't mind that, at least cut it back. -Fnlayson 14:01, 25 July 2007 (UTC)
    • Sorry, perhaps it wasn't clear. This is a replacement just for the current intro, "Explanation" and "Convenient Definition" sections - the first part of the article. I wasn't proposing at this stage making any changes to the rest of the article. I think that the examples are important, but I take your point that it seems a little too detailed. I have amended the above to cut down on the detail. Matt 13:08, 26 July 2007 (UTC).
  • I've now replaced with the above, overwriting a recent change claiming:
g-force (also gee-force, gee-loading) is a non-SI vector measure of force, where 1 g (pronounced [dʒiː]) is defined to be the force an object would experience by gravity at the surface of the earth (the units are newtons or pound-force).
This is wrong. The "gee" (symbol g) is a unit of acceleration, not force. In any case a unit can't be defined as the force "an object" would experience -- it depends on the object. Matt 12:39, 28 July 2007 (UTC).
Agreed. 1 g is the acceleration an object experiences on the Earth's surface. -Fnlayson 16:12, 28 July 2007 (UTC)
If we are talking about g-force, then it is a force. It is described by the acceleration which causes that force. Lets try to get this right. Rlsheehan August 12, 2007
  • Resulting force has nothing to do with it. That's a reaction force, internal force. G-force is an acceleration divided by acceleration of gravity so it is in g's. Having force in the name does not mean anything, since its units are g's not force units. -Fnlayson 03:17, 13 August 2007 (UTC)
  • I agree that "g-force" is a misnomer. Using this name confuses many people about force vs acceleration. If we call it a force, then it should be a force. It can still be described by the accleration which causes it. Rlsheehan Aug 14, 07
*It is certainly acceptable to report accelerations in the non-SI unit of g-s: see also Shock (mechanics). The confusion is that we are trying to call this a force. Perhaps a new first paragraph like this might help:
"g-force is a comomonly used term which can have two different but related meanings: 1) the acceleration on an object or person expressed in gs and 2) the reaction force resulting from an applied acceleration, expressed in gs." Rlsheehan Aug 13, 07
I've removed statement 2 since a force cannot be "expressed in g's" — any more than velocity can be expressed in kilograms, or time expressed in litres. The g is a unit of acceleration and that's that. Force per unit mass could be expressed in g's though. I think I mentioned that in the article at one point, but it got taken out for some reason. Matt 00:09, 30 August 2007 (UTC). —Preceding unsigned comment added by 86.134.55.114 (talk)
The item we are discussing is g-force, thus we must include the force interprretation. Yes, the term is probably a misnomer, but ,it is here and we can discuss it. It can be a force described by the acceleration which causes it: the causing acceleration can be described in terms of gs. Rlsheehan 01:56, 5 September 2007 (UTC)
Yes, it is important to start with a correct lead paragraph. The subject is g-force so force must be included in the lead paragraph. Otherwise, change the title. Rlsheehan 14:12, 5 September 2007 (UTC)

weight or force

in the 'human g-forces' section it says "a weight of 1g" a few times.

g is in N/kg and a weight is in kg, so this seems incorrect to me.

Any suggestions?

Mushlack 20:00, 4 August 2007 (UTC)

  • Weight is a force by scientific and tehnical definations. The SI unit for force is Newton (N) and the SI unit for mass is kilogram (kg). But the acceleration of gravity is not a weight either. So the wording should be adjusted/corrected. -Fnlayson 20:39, 4 August 2007 (UTC)

Italicization

Is the g in this article really properly italicized? Robert K S 07:42, 21 September 2007 (UTC)

  • I had the same thought, assuming you're talking about the "g" in "g-force" (rather than the standalone unit symbol). I have not found any dictionary that italicises the g, and unless anyone can provide some authority that says it should be italicised I propose the italics should be removed throughout. Matt 00:43, 23 October 2007 (UTC). —Preceding unsigned comment added by 86.136.195.74 (talk)
    • I've also looked at a selection of pages thrown up by Google, and basically I can't find anyone who italicises the "g" in g-force, so I've removed it. If you disagree and think it should be italicised then we need a solid authority I think... Matt 02:05, 31 October 2007 (UTC). —Preceding unsigned comment added by 86.150.100.198 (talk)

Eyeballs

Just a quick point: in the part about human tolerances, various references are made to difference tolerances with "eyeballs-in" or "eyeballs-out". Perhaps there should be an explanation of the term? I'd put it in if I knew what it meant myself, but I really don't... anyone else have a clue? Is it about eyes being open or closed? Eyes being slightly popped out of their sockets? Thanks. Hagger 19:09, 17 October 2007 (UTC)

Yeah, an eyeballs-out g-force 'tries' to pop the eyes out, an eyeballs-in g-force 'tries' push them in. It must be emphasised that it doesn't succeed in either case in any survivable situation ;-)- (User) WolfKeeper (Talk) 01:04, 17 December 2007 (UTC)

Formula One data

I'm skeptical about the Formula One data must be wrong. On a level road, with no airfoil, the greatest acceleration a car can have is mu*g, where mu is the coefficient of static friction, and g is the acceleration of gravity. Since mu for rubber on asphalt is no more than about 0.5, the greatest acceleration or deceleration you can have is about 0.5 gees. Unless these figures are referring to banked turns, or the cars have airfoils that can generate a downward force equal to 10 times the cars' weight, I don't think the article can be correct. Is there a source for these numbers?--76.81.160.198 (talk) 03:44, 10 December 2007 (UTC)

Your figures are way off. Standard cars can pull about .92 g on a dry road. Motorbikes with relatively sticky tires can pull over 1.2 g. Formula one cars have sticky tyres and downforce at maximum speed of about 5 or 6 times their own weight or more due to groundforce (predominately), but also the wings help some as well.- (User) WolfKeeper (Talk) 04:16, 10 December 2007 (UTC)
Oh yeah, and formula 1 cars go fast enough that just lifting off at high speeds gives about 1g deceleration (with the 'help' of the rear wing); putting the brakes on as well adds another 4g or so, even though they have relatively small front tyres.- (User) WolfKeeper (Talk) 04:20, 10 December 2007 (UTC)
Okay, if the airfoils really do produce a force many times greater than gravity, then the figures in the article are plausible.--76.81.160.198 (talk) 22:03, 16 December 2007 (UTC)
Oh yeah, massive downforce. Somebody calculated that a formula one car could theoretically drive continuously upside down from about 100 mph, but fortunately (or unfortunately), there's no upside down tracks anywhere to try this ;-)- (User) WolfKeeper (Talk) 01:01, 17 December 2007 (UTC)
I noticed that there is citation for the g-forces that Formula One drivers usually experience. I think that the figures are okay but they should be verified by a reliable source. --Cryonic07 talk ° contribs 21:36, 9 June 2008 (UTC)

Punch and kicks?

So... a punch or a kick to an applied area can actually reach beyond 5 or 9 g, relative to a cough or sneeze?

88.105.47.71 (talk) 22:54, 14 September 2008 (UTC)

Yes, but these are usually under the category of Shock (mechanics). Rlsheehan (talk) 16:19, 15 September 2008 (UTC)

Italicizing

It appears that some Web sites might be saying g is italicized because they are now parroting Wikipedia. Granted it might be a *splendid* idea to not have the g for acceleration be the exact same symbol as that for the SI unit gram, but to just flat state that the g (acceleration) is italicized must be properly cited. For on thing, italicizing a unit symbol is a colossal violation of an even more important principle that only variables are italicized; unit symbols are always roman (according to the SI Brochure section 5.1). Note too, this NASA page and this medical site. Note too this account of Colonel Stapp, the rocket-sled guy. Or Splung.com/Physcis. All use roman g. I’ve never seen an italic g in aerospace publications. This included Aviation Week & Space Technology, a magazine I subscribe to and which is the preeminent, authoritative trade publication. As for confusion with the gram, note as you read through these articles, no one with any common sense is for a moment confused and thinks that Stapp was exposed to “40 grams.” Besides, regardless of whether or not g ought to be italicized, it is not the job of Wikipedia to advocate change by suggesting in a factual way that “this is the way it’s done” if it is actually not done that way in the real world.

It seems to me that if we are going to cite some source that effectively says that NASA is doing it all wrong, whomever it is we’re citing oughta have some serious credentials. Greg L (talk) 05:42, 13 January 2009 (UTC)

I think that those writing 5 g simply mean five times the variable g (i.e. the magnitude of the local gravitational field), and in many cases the difference between it and the defined value 9.806 65 m/s2 is irrelevant. (You still italicize the speed of light c, even if you are using it in a way typical of units of measurement.) But I agree that I would not italicize g if I meant the unit of measurement equal to 9.806 65 m/s2 exactly, by definition regardless of local gravity. -- Army1987 – Deeds, not words. 13:24, 13 January 2009 (UTC)

Clearly not Army. The article appears to have been written by someone who tried to Change the World to Be a Better and Brighter Place™©®. This article states as follows:

The g /ˈdʒiː/ is a non-SI unit equal to the nominal acceleration of gravity on Earth at sea level (standard gravity), which is defined as 9.80665 m/s2 (32.174 ft/s2). The symbol g is properly written both lowercase and italic[citation needed] to distinguish it from the symbol G, the gravitational constant and g, the symbol for gram, a unit of mass, which is not italicized.

I put the {cite} tag there, otherwise, it would have appeared to be uncontested, authoritative fact.

And this quotation from this article:

Thus, in a simplified scenario where accelerations are assumed to act only upwards (positive) or downwards (negative), calculating g-force simply amounts to subtracting the acceleration (relative to the Earth) due to Earth's gravity (1 g in the downwards direction) from the object's acceleration relative to Earth. Since we are taking downward acceleration as negative, this is equivalent to adding 1 g. So, for example:

  • An object at rest with respect to the Earth experiences a g-force of 0 g + 1 g, or just 1 g ("normal weight").
  • An object in free fall (accelerating downwards at 1 g relative to the Earth) experiences a g-force of −1 g + 1 g = 0 g ("weightless")
  • An object accelerating upwards at 1 g relative to the Earth experiences a g-force of 1 g + 1 g = 2 g ("twice normal weight")
  • An object accelerating downwards at 2 g relative to the Earth experiences a g-force of −2 g + 1 g = −1 g ("negative g").


It also appears to me to be misinformation propagates to articles that link here. For instance, look at the second paragraph of Sprint (missile). It says The Sprint accelerated at 100 g, reaching a speed of Mach 10 in 5 seconds. The same thing occurred on our Shockwave (Drayton Manor Theme Park) roller coaster article: italicized g.

It is extremely hard to prove a negative (prove that just because I can’t find an authoritative source saying that g is italicized, that one doesn’t exist). However, the only “sources” I can find seem to be amateurish, tertiary ones that—unfortunately—took their guidance from here. The long-standing rule that units are roman and variables are italicized underlies why real-world usage by NASA and industry use “g”. Industry doesn’t seem to have followed Wikipedia’s lead into a Better and Brighter Future. Check out the spec page for this accelerometer or this one by Honeywell. They all use “g”.

It appears that article used italic g from the very beginning as some sort of house style to avoid confusion with the gram. Unfortunately, we can’t do that. If one examines any other encyclopedia, one will see that they don’t perceive a need to try to change the world because the same unit symbol means two different thing across their publications. Examine this first edit by Wolfkeeper. It could also be that he simply copy/pasted an article from elsewhere and didn’t advance such a notion himself. I’ve alerted him on his talk page.

I’ll give a full 24 hours for someone to cite this (or make a valiant effort to defend it because “it oughta be that way”), and then I will see if some bot operators can help correct all the articles that link here—there are about a thousand of them. Greg L (talk) 17:35, 13 January 2009 (UTC)

I think the general rule is that where a quantity symbol (such as g for gravity or m for mass) might conflict with a unit of measurement symbol (such as g for gram or m for metre), you should italicize the quantity symbol and leave the unit of measure symbol in roman type. My source for this is the Canadian government style manual (The Canadian Style, Dundham Press in co-operation with Public Works and Government Services Canada). Since NASA is in the US, and the US is somewhat out of step with the rest of the world as regards units of measure, this issue may not arise as often for them as it would for organizations in other countries, where the gram is the standard unit of mass. Note that g for gravity is not really a unit of measure, it's really a constant, equal to the average rate of gravitational acceleration on this particular planet (9.8 m/s2).RockyMtnGuy (talk) 17:01, 13 January 2009 (UTC)
  • RockyMtnGuy. First the facts. The article (incorrectly as far as I can see) states as follows:
The g /ˈdʒiː/ is a non-SI unit equal to the nominal acceleration of gravity on Earth at sea level (standard gravity), which is defined as 9.80665 m/s2 (32.174 ft/s2). The symbol g is properly written both lowercase and italic[citation needed] to distinguish it from the symbol G, the gravitational constant and g, the symbol for gram, a unit of mass, which is not italicized.
The g is clearly a unit of measure and it is used that way in the real world. 100 g by definition is 980.665 m/s2. For a 0.1% accuracy transducer, 100 g is 981 m/s2. That’s what the unit means. The article further clearly states that the unit symbol (representing the value of acceleration) is italicized. This flouts the rule observed in all good science that unit symbols are always roman text and variables are always italicized (SI Brochure section 5.1). Further, it flouts all real-world practice by any scientist or academic or engineer experienced in the art of acceleration.

As regards g as a variable, if one is writing a formula where acceleration is a variable, one customarily uses a, as in F = ma. I’m sorry, but it is not passing my “grin test” here that F = mg is a common way of doing it, nor that NASA is out in left field here.

An important point is it is not Wikipedia policy to use the Canadian Manual of Style; we follow broadly accepted, internationally recognized, real-world practices. Secondly, you are misinterpreting what the Canadian government style manual is saying. They don’t mean confusion arrises if g (acceleration) and g (gram) are “in the same encyclopedia”, they mean precisely what they said: “where a quantity symbol (such as g for gravity or m for mass) might conflict with a unit of measurement symbol (such as g for gram”).

This potential for real-world confusion doesn’t happen too often, where one must discuss grams and gees in the same article. For instance, this account of Colonel Stapp, the rocket-sled guy is rather common. So too is this NASA page. Both speak to the issue of accelerations and don’t make mention of the gram; ergo, there no conflict where confusion might arise. It is even less often that one mentions grams and gees so often in the same article that one needs to use unit symbols “g” for both. Nevertheless, the requirement to discuss mass and g's in the same document does happen if you are a manufacturer of accelerometers and they need to provide technical specs of the transducers themselves. The practical way to avoid the confusion is just use kg for mass, as is done in the real world by Honeywell with their accelerometers (data sheet). In that data sheet (obviously written for a European audience), they write Weight, AG111: 0,03 kg [1 oz]. An even better way, IMO, would be to simply write out the unit name: Transducer weight: 30 grams or Transducer weight: 0.03 kilogram since this pulls the rug out from under any arguments that writing “kg” might lead someone to think that weight is being measured in kilogees (although that doesn’t pass any realistic “grin test” either).

As I wrote above, the vast, vast majority of authoritative organizations and companies such as NASA and the manufacturers of instruments that measure g-force use the unit symbol as all unit symbols must be: roman (upright) text. We must follow real-world practices here and certainly must not flout fundamental practices observed in all proper mathematics and science. We should also avoid the misperception that just because there is technically a potential for confusion, that there is a genuine real-world problem. Examine, for instance, this hypothetical: The lake in 1999 measured only 2.6×1013 litres but we measured 2 gal notwithstanding its lack of volume. The world doesn’t need us POV-pushing and inventing house styles based on perceived shortcomings with the way the world really works. Greg L (talk) 18:04, 13 January 2009 (UTC)

I'm not quite sure who is POV pushing. We have a reliable source that says that having g in italic form is valid.- (User) Wolfkeeper (Talk) 22:58, 13 January 2009 (UTC)
  • I assume you are referring to the Canadian Manual of Style? That is not what they said. “Valid” only in under very special circumstances. What they said (and mean) is that if you have a document where the symbol g for gram is simultaneously being used with the gee, to put the gee in italics. Short of this, the unit symbol for gee (g) follows the convention universally used for unit symbols and as it is used by the rest of the world. What is clear is that you don’t always (in fact, quite rarely) make the unit symbol italic. Further, there are infinitely more superior ways to avoid such confusion; just write out he word gram. If someone wants to put that Canadian bit of advise (regarding articles where there is potential for conflict) into our article, that’s fine with me, but it needs to be properly and fully cited.

    I applaud your desire to banish all potential for confusion from the halls of Wikipedia. But the onus really needs to be centered squarely upon the facts and standard practices. How many manufacturers of accelerometers can you find that use g in italics? I’ve cited two, above, that use it in roman. Or do you think they—like NASA—are simply all wrong here? Greg L (talk) 23:13, 13 January 2009 (UTC)

Quite frankly, you just seem to be trying to force a US convention on the entire wikipedia, this all seems very WP:POINTy to me. NASA is a US-government organisation that historically has exclusively used imperial units (but is moving to almost exclusively use SI now), and hence historically would have seen absolutely no reason to use the italic form. All of the other manufacturers you quoted were American. The wikipedia by and large (but not exclusively) leans towards SI units, and this generally encourages the use of g rather than g.- (User) Wolfkeeper (Talk) 00:13, 14 January 2009 (UTC)
FWIW I just checked 'Rocket Propulsion Elements' (7th edition) by Sutton, which is about as near to being a standard rocket handbook as you can get (and he's an American author), and on page 214 he refers to zero-g. I just don't think that your suggestion that the entire wikipedia be changed is going to fly with notable examples like that. I'm also finding that g0 in general on the web, is nearly always written in italics where this is possible; and again Sutton uses this throughout.- (User) Wolfkeeper (Talk) 00:13, 14 January 2009 (UTC)
  • We seem to be short on facts—at least the kind you like. Please produce verifiable sources saying that g is generally supposed to be italic. Please cite the Canadian Manual of Style, in full. If it is a Web address, please provide that. If it is a book, please cite the ISBN and provide the full wording of what it says on the subject. Let’s get that much out of the way.

    As for your dismissing my links (NASA and two manufacturers of accelerometers) as being “American”, let’s examine the very first two Web sites I’ve come across for foreign suppliers of accelerometers: Active Robots in the UK, and Farnell in Australia. They are, not surprisingly to me, using roman g.

    Further, I utterly reject your method of “proving” anything by (supposedly) citing a book of yours that uses an italic g. That isn’t verifiable, and is also anecdotal. The question is, what is the world-wide standard. And if the US style is different from the world-wide standard, then our article needs to state as much. Please demonstrate what you suggest: that world-wide practice outside of the U.S. is italic. The very first two sources say this is not so. I note also, curiously, that you dismissed my manufacturers as being American (suggesting that the world-wide practice is italic) and then didn’t provide any Euro manufacturers or distributors of accelerometers yourself. Greg L (talk) 00:58, 14 January 2009 (UTC)

I don't think you understand. Sutton is the rocket text book. He's probably more authoritative than NASA by and large. And the 7th edition was the one that converted to SI.googlebooks Look, I'm not going to argue this any longer, this is a waste of time, I've made slight changes to the article. Any attempt to systematically remove italic use from the wikipedia is going to be reverted as being undue weight and failing to represent a global point of view. I agree that non italic 'g' is used in some cases, particularly in America, and maybe in some or all accelerometer manufacturers literature (particularly if they want to sell into the American market I imagine), but that's not enough.- (User) Wolfkeeper (Talk) 01:23, 14 January 2009 (UTC)
  • You seem to be short on verifiable facts—at least the kind of facts that you are founding a shaky premiss upon. A book proves absolutely nothing. Please produce verifiable sources from an internationally recognized standards body saying that g is *generally* supposed to be italic. Please cite the Canadian Manual of Style, in full. From RockyMtnGuy’s description, it sounds like this is not what they are saying. If it is a Web address, please provide that. If it is a book, please cite the ISBN and provide the full wording of what it says on the subject. Let’s get that much out of the way.

    As for your dismissing my links (NASA and two manufacturers of accelerometers) as being “American”, let’s examine the very first two Web sites I’ve come across for foreign suppliers of accelerometers: Active Robots in the UK, and Farnell in Australia. They are, not surprisingly to me, using roman g. As for NASA being American (and how their practices are at odds with the rest of the world), check out ESA’s GOCE Web site. I’m sorry, but the World-Wide practice by WP:reliable sources is clearly roman.

    Finally, your statement The wikipedia by and large (but not exclusively) leans towards SI units, and this generally encourages the use of g rather than g is a non sequitur; yes, Wikipedia tends towards SI, but that doesn’t in the least prove that the world flouts a world-wide standard that unit symbols are always roman—italic is reserved strictly for variables. In fact, it demonstrates the opposite, since the rule of the SI is clear on this subject: Unit symbols are printed in roman (upright) type regardless of the type used in the surrounding text. This is in keeping with the long-standing practice in mathematics and engineering since the at least the time of Newton.

    Finally, please don’t threaten to editwar over this (Any attempt to systematically remove italic use from the wikipedia is going to be reverted as being undue weight and failing to represent a global point of view.). The only way to win here is to prove that the world-wide practice is italic and I’ve just demonstrated that the most reliable sources—world wide—is clearly roman. American manufacturers of accelerometers for measuring g-force, world-wide distributors of accelerometers, American space agency, European space agency. Simply threatening to editwar and revert doesn’t cut it. Give it up please; it’s a lost cause. Greg L (talk) 01:29, 14 January 2009 (UTC)

Greg, "only variables are italicized"? But then why do our articles on e (elementary charge) and e (mathematical constant) italicize e? Are they both wrong?--Goodmorningworld (talk) 05:10, 14 January 2009 (UTC)

I'd also like him to explain why he thinks a reference to a documents about SI units is binding on g when g isn't even an SI unit and so is outside the scope of the documnent! In other words he has only American references and a couple of advertising specifications by some companies trying to sell stuff on a web page. These weren't even PDF files or anything. This is all incredibly tendentious.- (User) Wolfkeeper (Talk) 12:57, 14 January 2009 (UTC)
This whole discussion is too weird for words. The whole point of using italics is to avoid confusing symbols for quantities (such as gravity) with symbols for units (such as gram). However, after a little Googling, I found that the final authority on the subject is the International Bureau of Weights and Measures (BIPM) and the issue was decided by the Conférence Générale des Poids et Mesures (CGPM) in 1901, where they decided that the standard acceleration due to gravity was gn = 9.80665 m/s2. See: Declaration on the unit of mass and on the definition of weight; conventional value of gn. The US National Institute of Science and Technology (NIST) followed their lead. Note that the symbol used was "gn". Italicized "g", subscript roman "n". Other symbols are often used, such as "g", "g","g0", "G", and "gee", but they aren't really internationally recognized.RockyMtnGuy (talk) 05:28, 14 January 2009 (UTC)
  • This is quite surreal for me too. Although BIMP may be the world authority, I don't think this is the relevant document. While it uses italicized "g", subscript roman "n", the footnote to the resolution states the italicised gn notation to be obsolete. Nowhere does this state categorically, infer or imply that gee is to be denoted by g, if you see what I mean. Ohconfucius (talk) 07:34, 14 January 2009 (UTC)
I just checked that, and I don't see anything that declares gn to be obsolete. They simply declare what the acceleration due to gravity is, but unfortunately fail to give it a symbol to denote it.- (User) Wolfkeeper (Talk) 14:00, 14 January 2009 (UTC)
I'm sorry, but it quite rightly says that kilogram force (kgf) is obsolete, not g or gn; you misread it.- (User) Wolfkeeper (Talk) 14:19, 14 January 2009 (UTC)
  • Yes. You are quite right Wolfkeeper. In 1901, before the Wright brothers first flew, the BIPM referred to one Earth gravity as gn. Are you suggesting that this, somehow, is relevant other than as a historical footnote about yet another BIPM proposal that was trampled into the dust by the real world? The BIPM currently says that one writes 22 % and not what everyone really does on this pale blue dot, which is 22%. It doesn’t matter what symbols were used back in the horse & buggy days where steam engines were the fastest things around. We don’t try to change the world here as volunteer editors on Wikipedia; we simply reflect the facts. And we also don’t put undo weight on side issues, like writing here that The proper way is to say “I am making a 3 gn turn.” The real world doesn’t follow this and we won’t be writing that it is the “recommended” or “proper” practice. As you may have noted, this article is not titled gn-force. We might mention this in a History section (if we manage to get that far). Greg L (talk) 04:43, 15 January 2009 (UTC)

The cover photo on "Rocket Propulsion Elements" shows NASA's Space Shuttle; I guess Mr. Sutton thinks that the folks at NASA aren't total nitwits. Wolfkeeper, you are right that his book uses g in italics,[1] but this is just one book. You weaken your position by dismissing the agency that built the Saturn moon rocket as inconsequential to the field of rocketry.

The references in this article are weak. The first for "The Canadian Style, Dundham Press" is incomplete. I could not find anything about this book or the publisher. Does it exist? A reliable source must be verifiable. The second has a Google book search to show the "gee" is common for acceleration. Most of the hits are fiction books. I am not sure that a raw Google search is a valid reference.

Wolfkeeper, you will need to find some reliable sources to show that the italic g is more common than the "American-only" practice of the roman g. Remember; most readers of the English Wikipedia are from the evil and ignorant United States. - SWTPC6800 (talk) 06:43, 14 January 2009 (UTC)

We don't have a policy of tailoring things for most readers; otherwise the entire wikipedia would be written in American english, and would have to be rewritten if our demographic changed. Note that there are far, far more English speakers in the world than are in the UK or North America. What's really happening here is that the sources picked for this discussion gave undue weight to America (perhaps unconsciously), and this has lead to this discussion very much getting off on the wrong foot.- (User) Wolfkeeper (Talk) 14:00, 14 January 2009 (UTC)
  • I'm here from the MOSNUM discussion. It strikes me that even the Canadian manual accepts or strongly implies a non-italicised 'g' is the universal default, only requiring italicisation when there is conflict. That being the case, I have changed the text accordingly. I feel that anyone who strongly feels g (gee in italics) is the default or international norm should validly source it. A reliable source should state specifically that it is used predominantly in its italicised form (and in what context, if nexessary), with a footnote naming the source and including the proper citation - we are obliged to be so specific as there may be others which contradict it. I do not feel mere use of ital-gee in any given textbook, without explaining the scientific notation, is sufficiently NPOV - it is even less justifiable seeing this appears to be strongly contested, and with good reason. Ohconfucius (talk) 07:19, 14 January 2009 (UTC)
  • Wolfkeeper et al.: I believe that Greg is quite right to insist that "g" not be italicised. He has long and broad experience in science writing, and his views transcend any one variety of English. Broader issues that cover such italicisation have been discussed extensively at MOSNUM talk and have been resolved such that "g" is rendered in roman face. Tony (talk) 09:33, 14 January 2009 (UTC)
The 'valid examples' he has given are universally American-centric or advertising copy and very poor quality. The convention is because of the SI system, but is not part of the SI system. He started off the discussion with threats of applying bots, and has been unreasonably argumentative, and has employed ridiculous arguments such as referencing articles that are specifically about the SI system that have nothing whatsoever to do with the issue in hand. He also started off with accusations of poor faith, that I was 'trying to change the world', when the evidence is actually to the contrary, that he is trying to introduce a non NPOV position, and he has not got any better even when quite reasonable references to its use have been given. It wasn't as if I had to struggle to find these references either, and related constants such as gn are wherever possible specified in italic form, even in the SI documents. In short, I want him to go away now, I don't think I should have to put up with this kind of bad faith garbage in the wikipedia.- (User) Wolfkeeper (Talk) 12:57, 14 January 2009 (UTC)

This started as a discussion in WP:MOSNUM. The point is that the canadian guideline is probably binding on us in the following way: we cannot predict when the 'g' unit is used whether a gram will later be in use elsewhere in the article. Therefore to keep the units distinct, it might a good idea to indicate that this is the preferred form in the wikipedia, without stating that other forms are actually wrong. I believe that that is the logic that is used by Sutton in using the italic g; no author would want to have to go through and check each page, and I don't think that we should either when authoring the wikipedia. So in my view the house style should be italic because of our common use of SI units, anything else is going to be too confusing and inconsistent. But other uses aren't wrong.- (User) Wolfkeeper (Talk) 13:46, 14 January 2009 (UTC)

  • Wolfkeeper, you are POV-pushing because you want something to be so. Wikipedia always goes with most-reliable sources. I’ve proven above that this planet’s manufacturers of accelerometers, academia publishing medical papers on g-force-induced bodily injury, and the world’s two largest space agencies (NASA and ESA) all use roman g exclusively. I’ve been patient in responding to your objections. You poo-poo’d NASA as for not knowing their butt from a hole in the ground and being “American”, and for being an organization that is only slowly adopting the SI. Then I showed you that the European Space Agency uses roman g. That didn’t seem to impress you either because here you are ranting about how it’s better as italic. Doesn’t matter.

    The problem here is there is a g proponent on Wikipedia who desperately believes g should be used and hopes the world will fall in line. The trouble, is, it is the other way around, Wikipedia follows the way the real world works. Notwithstanding the overwhelming evidence that the world-wide practice is overwhelming to use roman g, you want to state that is ‘most commonly’ or is ‘supposed’ to be g because of one, thoroughly forgettable book and a poorly referenced—and probably misquoted—passage from a Canadian Government manual of style that you’ve obviously never even seen yourself because you can’t cite the page and the entire text on that page. Now…

    This state of affairs is utterly absurd. The world isn’t using gn or any other suggestions by dueling standards bodies; as you are acutely aware, this article is titled “G-force”, not Gn-force. This article will follow the practices universally observed by all real-world, authoritative sources on this issue. When you can show me that—world-wide—most manufacturers of accelerometers use italic g on their data sheets, and when you can show me that the world’s two space agencies do the same, then this article will go with italic g.

    If you are so concerned about “confusion with g for gram”, you’ve got my blessing to write the whole paragraph about how to avoid that. Note that the manufacturers of accelerometers have chosen to just write on their spec sheets that the weight of their devices are “0.03 kilograms”. I suggest that you follow their lead when writing that section instead of insisting on blazing a new path for the manufacturers and ESA and NASA to follow; they seem to be doing just fine without the help. Greg L (talk) 16:47, 14 January 2009 (UTC)

I note that you are continually mischaracterising my position to an extreme degree, worse, you also are misquoting wikipedia policy.- (User) Wolfkeeper (Talk) 17:20, 14 January 2009 (UTC)
You say: Wikipedia always goes with most-reliable sources; but that's simply wrong. The Wikipedia is dominated by WP:NPOV which says that all notable positions are represented. That means you do NOT get to roll out bots and change the entire wikipedia to match your POV of what the majority (sic) real-world sources say when there are notable sources to the contrary.- (User) Wolfkeeper (Talk) 17:20, 14 January 2009 (UTC)
And I can only request again that you be a lot less tendentious in your discussion style here, it is in no way helpful. Please assume good faith.- (User) Wolfkeeper (Talk) 17:20, 14 January 2009 (UTC)
I also found it particularly amusing that Greg_L attempted to rewrite the introduction to define g-force incorrectly. It appears he doesn't even know what g-force is, never mind whether it is italic or not! If g-force was a simple measure of acceleration, then I would be sitting in a 0g environment, but in fact my g-force is 1g. It's actually the acceleration relative to the local gravitational field strength measured in multiples of g0, or some such definition.- (User) Wolfkeeper (Talk) 17:53, 14 January 2009 (UTC)
  • Exactly: “or some such definition”. I see why this article is in need of wholesale repair. As noted below in the following section, you haven’t understood all this time that gravity is an acceleration that is absolutely identical to, and indistinguishable from, an inertial acceleration. See General Relativity. Please stop ranting and start listening. Greg L (talk) 20:00, 14 January 2009 (UTC)
My original comment (see waaay above) was copied over from MOSNUM, so it lacks a bit of context here. I originally came to see what was happening because of a message on MOSNUM. However, what I can say is:
  • This article as a whole lacks scientific rigor. A lot of the dispute revolves around the fact that a lot of people are unclear what it is being talked about.
  • The name of the article itself is a misnomer. G (or g) is not a force, it is an acceleration due to gravity.
  • The symbol g is not a unit, it is a quantity. By itself, g is a variable who's value changes from place to place.
  • The symbol g in its non-italicized form conflicts with "g", the SI symbol for gram, so it cannot be used in articles using "g" for gram. Since SI is the global standard system of units, that is a serious issue.
  • What is talked about here is not g, but gn, (which is the official standardized average value of g on Earth) as recognized by the International Bureau of Weights and Measures (BIPM) and the US National Institute of Standards and Technology (NIST).
  • The official value of gn, which everyone uses, was adopted by the Comité International des Poids et Mesures (CGPM) in 1901. For the resolution, see here. Note that it was used in defining the now obsolete unit kilogram force.
  • For the NIST version of gn, see here. Note that it is listed under "Fundamental Physical Constants" and not "Units".
  • See also the NIST list of conversion factors see here Note the line "Caution: The units listed in column 1 are in general not to be used in NIST publications", and that the first unit listed is "acceleration of free fall, standard (gn)"
  • NASA is not really a reliable source of ways to handle units. In 1999 they actually had a satellite burn up in the atmosphere of Mars because their satellite was designed in metric units, and their sub-contractor transmitted the course corrections in imperial units.
  • I quoted the Canadian Style manual because Canada is something of a microcosm of the world as a whole. It has two official languages and officially uses the SI system, plus unofficially both the American and British imperial systems.
  • The Canadian Style manual reference is: Public Works and Goverment Services Canada (1997). The Canadian Style - A Guide to Writing and Editing. Dundum Press Limited. ISBN 1-55002-726-8. {{cite book}}: Check |isbn= value: checksum (help).
  • The Canadian Style manual follows the SI Standards set by the BIPM. The BIPM sets the global standards for the SI system.
  • The US NIST follows the BIPM standard as well, with minor variations.
  • For the NIST guide to using the SI system from the American perspective, see here.
  • In the NIST Guide to Using the SI System, be sure to read pages 39-44 on "Writing unit symbols and names, and expressing the values of quantities", because it is the official American standard for writing scientific papers.
Cheers.RockyMtnGuy (talk)
  • You clearly haven’t read all the threads here. Every one of your points has been addressed and refuted. As was amply demonstrated with our three-year experiment to follow the IEC’s proposal on binary prefixes, where we wrote “kibibyte” (KiB) instead of what the world really uses: “kilobyte” (KB), it is wrong for Wikipedia to embrace standards that the world ignores. You know that. NASA and the European Space Agency and the manufacturers of accelerometers and the distributors of accelerometers and anyone who does scientific or medical work uses “g”. We follow the way the world works. Greg L (talk) 18:22, 15 January 2009 (UTC)
I'm not convinced by your argument here Greg_L. The very first book I grabbed (Sutton) did follow this italic convention, and this has been verified by others here. Is that pure coincidence? I don't know without further research; but it's a bit strange, I would not have expected Sutton and the other authors to make up the convention. I checked the ESA page you indicated, and it did not support your claims either, it didn't appear to be talking about g-force, it appeared to be talking about standard gravity and (eroneously) calling it 'g' force.ESA’s GOCE However RockyMtnGuy claims that the Canadian Style guide supports this usage, but this has not been verified by others here. Can he quote the exact passage that supports this?- (User) Wolfkeeper (Talk) 19:11, 15 January 2009 (UTC)
  • It doesn’t matter what the BIPM or the Canadian government says, nor the Liberian government says, nor what the IEC says (the people who proposed “kibibytes”). We do not follow what the IEC says about the binary prefixes (MiB v.s. MB) in our computer articles because the real world does not use them. We tried that for three years before realizing it was a collosal mistake to have done so when no computer manufacturer and no computer magazine used them. Nor do we follow (*even*) the BIPM if their recommendations aren’t observed in the real world. We completely flout the BIPM when they say it is cm3 or ml when we write the Kawasaki 750 cc motorcycle engine. Why? Because the real world doesn’t work that way. Want another example? According to the BIPM’s SI manual of style, 5.3.7 Stating values of dimensionless quantities, or quantities of dimension one, When it [the percent symbol] is used, a space separates the number and the symbol %. This practice has not been well adopted with regard to the % symbol, is contrary to Wikipedia’s Manual of Style, and is not observed here. Wikipedia does not require us to write we had 22 % observance of common-sense rules by editors on Wikipedia just because some standards body says we should. Don’t start poo-pooing the European Space Agency now. They write on their Web site on the gravity experiment probe as follows: At school we generally learn that g = 9.8 ms–2. We all know what they mean. And these guys are as SI compliant as anyone else you can point to.

    Now give it up. I’ve shown that the world’s space agencies use roman g (not gn) and so too do the world’s manufacturers of accelerometers, as well as any real-world scientific uses of accelerometers. You don’t have to like the fact that the symbols for gee and gram are the same; just realize that this is the way the real world works. And to also accept that goal for any encyclopedia is to communicate with minimal confusion so that readers can learn about a subject and are primed as well as possible to learn even more in their studies elsewhere. We don’t accomplish that end by using symbols or units of measure that aren’t used in the real world. Greg L (talk) 20:42, 15 January 2009 (UTC)

It does matter what the BIPM says, because they set the international standard for metric units. Since "cc" is an obsolete symbol for "cm3, we should convert all instances of the former to the latter. However, nobody I know uses "kibibytes", so I think we can ignore it, and the Canadian Style manual specifies that there should be no space space between a number and the % symbol, so the Canadian government disagrees with the BIPM on that point. In addition (this is probably too radical an idea for Wikipedia), the Canadian Style manual says that, while SI unit abbreviations should never be followed by a period, imperial unit abbreviations should always be followed by a period (e.g. "cm3" versus "cu. in."). However, the whole point is to avoid ambiguity in articles. Since the SI system uses most of the Roman alphabet and some of the Greek alphabet, the normal solution in scientific papers is to use italics to distinguish letters used for quantities from letters used for SI units. Writing for school children is a different issue.RockyMtnGuy (talk) 04:22, 16 January 2009 (UTC)
  • I agree that we're not formally bound by any standard, but we should at least evaluate existing standards before picking one for ourselves. Your idea Greg_L basically seems to be that you tell us what we are going to do, and that you ignore any existing conventions that are contrary to that? Who died and made you God? Nobody. If RockyMtnGuy can quote worldwide standards, then we can at least evaluate them. We may or may not decide to follow them (at the moment I'm leaning away from italic form somewhat), but Just Do It Greg_L's Way Because He Says So(tm) is a heap of garbage that I cannot ever agree to. FWIW you don't even follow the editing standards of the wikipedia's talk page; exactly who says you get to stick a * in front of every comment you make???? Why should we trust you to help set the wikipedias guidelines when you make up your own?- (User) Wolfkeeper (Talk) 05:09, 16 January 2009 (UTC)
  • P.S. I’ll take something back, RockyMtnGuy, when I responded to your last post. When you wrote This article as a whole lacks scientific rigor, I couldn’t agree more. In fact, it is an understatement. Greg L (talk) 23:21, 15 January 2009 (UTC)
True, the problem is lack of rigor and clarity in the article. It is very foggy on the concepts it is talking about. You need to use a style guide which allows rigor and clarity to be achieved, keeping in mind that this is a globally readable medium.RockyMtnGuy (talk) 04:22, 16 January 2009 (UTC)

Just my two cents. A physical quantity and a unit can be equal by definition and still stay a physical quantity and a unit. For example, the NIST list of CODATA recommended values for physical constants defines one of them as . I guess the same applies here: gn = 1 g. I'm not going to insist more on this because 1) I'm already busy enough, and 2) I barely know that this unit of measurement exist. But, given that I often read things I could be expected to be very marginally interested in, just because of boredom (that's more-or-less what my Sewer Cover Barnstar says), if there was an exception to the rule of upright symbols for units I would likely (i.e. about 25% chance) have sometime encountered it, and given that I'm a markup fanatic (i.e. ones who uses boldface for vectors even in handwriting), if I had ever encountered it I would very likely (i.e. about 90% chance) remember about it. (This doesn't prove that no such exception exists, of course.) -- Army1987 – Deeds, not words. 11:03, 16 January 2009 (UTC)

When I read great G or non italic g for g-force then know I that the writer have no glue about physics or works sloppy or have problem with the code page (contain no italic). First G stand for the gravitational constant or weight, but not for g-force! 2.2 SI derived units What mean [2] ? Right gn and CODATA the same. NASA (who mixed gravitional constant and g for g-force) and Honeywell are not an Institute for Standardization! The Internet is the wrong place for this recherche, through lack of the right codepage! We should take a look in physic books and technical formula libraries (Gieck and Bosch etc.) all wrote g small and italic. Kinematik Kinematik [3]or Gerthsen Physik ISBN 978-3-540-25421-8 or Dr. Ernst J. Feicht * Dr.Ulrich Graf ISBN 3-7632-1617-0 Page 58 etc. --HDP (talk) 18:04, 16 January 2009 (UTC)

g force

An editor added a fact tag with the comment "g-force isn't actually a measure of acceleration, it's acceleration relative to gravitation field." This is not true. F=ma (newtons 2nd law). gforce & mass = force. Thus, by definition, gforce = acceleration. It is expressed in units (gs) that are equal to 9.8 m/s2 per g. Hipocrite (talk) 17:53, 14 January 2009 (UTC)

Sorry, that's wrong. I'm sitting at 1g but my acceleration is zero. Acceleration is m/s^2; m/s = zero.- (User) Wolfkeeper (Talk) 17:57, 14 January 2009 (UTC)
You raise a good point that gforce has a "base" unit of -1. I've made that clear in the intro. Hipocrite (talk) 18:01, 14 January 2009 (UTC)
Do you have a reference for that either????? In my opinion it's also clearly wrong and still uncited to boot.- (User) Wolfkeeper (Talk) 18:14, 14 January 2009 (UTC)
I don't see how it dosen't follow from everything else written. Perhaps you could define what you believe the g-force to be, simply worded. Hipocrite (talk) 18:15, 14 January 2009 (UTC)
I'd like it to be defined the same way as a reliable source, hence the citation request.- (User) Wolfkeeper (Talk) 18:23, 14 January 2009 (UTC)
Good to go - "Although the term "g force" is often used, the g is a measure of acceleration, not force." [4] Hipocrite (talk) 18:29, 14 January 2009 (UTC)
I don't find that that is a definition, more of a comment. And a lot of the article seems to be talking about acceleration due to gravity which is a distinct concept to g-force as discussed here.- (User) Wolfkeeper (Talk) 05:01, 16 January 2009 (UTC)
  • Hipocrite, is entirely correct. The g is a unit of acceleration. It is 9.80665 m/s2. Period. Period. Regardless of axis. The baseline you want to measure it against depends on the need, just like pressure may be gage pressure (psi-g) or absolute pressure (psi-a). In the case of the former, the pressure is measured with respect to background atmospheric. You might measure 30 psi-g in a tire but there is 44.7 psi-a (at nominal sea level) in absolute terms. The same applies for accelerations.

    Usually, vertical accelerations for dynamic situations are measured with respect to barycenter of the Earth. Thus, at sea level at around 53° latitude on the geoid, one will be experiencing an acceleration of 1 g when one has no further vertical acceleration with respect to the ground. If one accelerates at 9.80665 m/s2 in a plane with respect to the ground, the total acceleration is 2 g. However, if one has an inertial navigation instrument, its three-axis accelerometers are zero’d when it is stationary with respect to the surface of the Earth.

    Wolfkeeper, you are displaying WP:OWN issues here and are also exhibiting a breathtaking lack of understanding of basic physics when you wrote Sorry, that's wrong. I'm sitting at 1g but my acceleration is zero. Acceleration is m/s^2; m/s = zero. Einstein showed that with his “light beam across an elevator” thought experiment that an inertial acceleration relative to the Earth’s surface is identical to and indistinguishable from gravity; they are one in the same. F = ma does not go out the window, Wolfkeeper, depending upon the axis one measures. A 1-kilogram object sitting stationary on the floor, per F = ma, is being accelerated at 9.80665 m/s2 due to gravity and that is why it generates a gravitational force of 9.80665 newtons downwards.

    I’ve got a lot more work ahead of me to fix this article. If your writings here on this page, Wolfkeeper, are an accurate representation of your knowledge on basic physcis, then you obviously don’t yet understand enough to be doing any good here right now. I suggest you start with General relativity to understand something elementary like how gravity is an acceleration—like any other—and that Hipocrite is entirely correct. I’ve reverted your edits since they are entirely incorrect and are POV-pushing. This article is sorely lacking and needs to be consistent with MOSNUM, basic scientific principles, and the way the rest of the world obviously and clearly works. Greg L (talk) 19:14, 14 January 2009 (UTC)

Feel free to remove citation requests and not cite anything, go right ahead. Is there a single wiki policy you haven't broken multiple times today????- (User) Wolfkeeper (Talk) 19:30, 14 January 2009 (UTC)
  • Wikipedia is a collaborative writing environment. Friction between editors goes way up quickly when an editor isn’t listening to what others are saying. Sit back and be patient. The real world calls and I have stuff to do. Fixing articles takes time. I do my homework and when all is said and done, this article is going to be correct; factual; balanced with respect to reflecting the most common, real-world practices; and will be well-cited. In the mean time, I suggest you afford Hipocrite much more latitude than you have so far; he, at least, has the basics of F = ma down pat and that will be a damn good start here. Greg L (talk) 19:37, 14 January 2009 (UTC)
You're the biggest hypocrite I have ever met on the wikipedia, and I have been here a long time, by a very long way indeed.- (User) Wolfkeeper (Talk) 19:40, 14 January 2009 (UTC)

Remain civil, you two. This is way overboard. Can you each explain what the problem here is, clearly and succinctly? Hipocrite (talk) 19:45, 14 January 2009 (UTC)

  • Wolfkeeper, I’m leaving your “citation” about the Canadian government’s manual of style in place at the moment in order to give you sufficient time to gain access to it. Based on your continued silence in the face of my repeated requests to cite the page number and quote all relevant text pertaining to italicizing, it appears you are currently only assuming what it says on the subject. When I cite Web pages, I provide a link so readers can see it themselves. If I cite books, and if it is practical to do so (one or two succinct points of fact), I quote the passage. Given that all the world’s authorities on acceleration (manufacturers of accelerometers and the space agencies) use a roman g, we need to make sure what the Canadian government manual of style really and fully says on the subject. That should give you something to focus on instead of uncivil name-calling. Greg L (talk) 19:52, 14 January 2009 (UTC)
  • The manual of style is avaliable on books.google.com at [5]. I reviewed the text, searching for "gforce" "g force" "g-force" "force" "SI units" and "italic." The only relevent text I found was in the italics section, 6.11 - which does not appear to substantiate italicizing "g" the unit. Hipocrite (talk) 20:34, 14 January 2009 (UTC)
  • Thank you very much, Hipocrite. There is indeed the potential for confusing g with gram, but the issue seems more imaginary than real based on real-life experiences with the space agencies and anyone else who deals with acceleration. Examine this hypothetical: The lake in 1999 measured only 2.6×1013 litres but we measured 2 gal notwithstanding its lack of volume. What do you expect when you click the links? Did I mean …but we measured 2 gal or …but we measured 2 gal? Clearly, the scientific world marches on notwithstanding the potential for confusion.

    The simple solution in those relatively rare instances where small amounts of mass needs to be discussed within a document that is focused primarily about accelerations is to use the SI base unit kilogram (or the gram) and to write out the unit of measure. This is in keeping with the actual, real-world practices of the manufacturers of accelerometers. That should be enough to ensure midwives don’t weep, boils don’t appear on our faces, our goats don’t lie down in the fields, and our crops don’t wither. For now, I am removing the citation as it appears to be false. So far, I am still on the first paragraph of the article. A huge amount of work remains. Greg L (talk) 20:50, 14 January 2009 (UTC)

  • What do you think of that lead paragraph, Hipocrite? I have endeavored to get a lead that is absolutely factual and succinct. Have I succeeded? If so, we can build from there. I’ve gotta go right now. Thanks again. Greg L (talk) 20:54, 14 January 2009 (UTC)

{fact} tags and basic physics

Please don’t disrupt Wikipedia to make a point. Basic physics should not have to be explained. Your above writings demonstrate that you not only have insufficient understanding of physics, you have an incorrect understanding of physics. Notwithstanding that I shouldn’t have to educate you here (simply getting out of the way and letting me correct this article should suffice), I will nevertheless provide a short tutorial here. Sit back and learn. The measure of g-force is the measure of accelerations. Period. Inertial acceleration is precisely the same as gravitational acceleration. Even for a light beam, gravity and inertial acceleration are the same (see General relativity). If you can’t wrap your mind across that concept, go get yourself a three-axis accelerometer—even an iPhone will do—and tilt it around and see what happens. Then go jump off a roof (please do so safely) and see what happens. You will see that you can make any axis on the accelerometer respond to one g of Earth gravity just as you can by getting into an automobile and hitting the brakes. There will always be this pesky “Earth gravity” signal that you can make leak into any of the axis depending on how you hold it.

I’ll be doing most of my repair on this article starting over the weekend. Greg L (talk) 19:11, 16 January 2009 (UTC)

P.S. I fully intend to (slowly) get this article good enough for Good Article (GA) status. I’d tell you about the last article I worked on, which recently earned GA status, but I’m afraid you’d try to go teach the world about how it’s all screwed up over there too. Getting this to GA will take a lot of time since this article has parts that are fouled up beyond all recognition, and has other parts that make a point in a very, very poor way. This article clearly has been the product of too many drive-by shootings over the years by too many amateur I.P. editors, as well as by a certain registered editor who hasn’t understood all this time that gravity is an acceleration that affects accelerometers. This article is in need of serious repair and revision. That means I’ll try to add content where possible. But some parts will be deleted as new passages slowly expand and later replace them. Don’t panic and leave your propensity for WP:OWN behind. Further, part of getting an article to GA status is to have an attractive, nearly decorative, photo with an illuminating caption. I would greatly appreciate it if you would stop snipping away at my heels as I do this. Greg L (talk) 19:37, 16 January 2009 (UTC)

I simply asked you to cite what you wrote. Apparently you can't do that or you wouldn't be trying to condescend to me. I find this... regrettable.- (User) Wolfkeeper (Talk) 19:40, 16 January 2009 (UTC)
And ummmm, no what you wrote is not quite right. When you jump off there's no signal, nothing leaks in, because you're following the geodesic (ignoring slight wind resistance). And that's one of the problems, gravity isn't an acceleration as far as g-force is concerned, but the reaction to it is if you stand on the ground or whatever. But you don't even need GR theory for this article, and I'm not convinced it's helpful to a lot of people, but mentioning it somewhere might be a good idea.- (User) Wolfkeeper (Talk) 19:40, 16 January 2009 (UTC)
  • No you are entirely wrong when you write “gravity isn't an acceleration as far as g-force”. Why do you think accelerometers indicate 1 g when they are sitting on a desk? Greg L (talk) 20:08, 16 January 2009 (UTC)
Yeah, 1g upwards, because the desk is giving a positive g relative to the geodesic. The gravity acceleration is downwards. You're scaring me here Greg_L; this is really basic stuff.- (User) Wolfkeeper (Talk) 20:15, 16 January 2009 (UTC)
The g-meter would usually invert it for display purposes though to give an effective gravity direction. But the acceleration is actually upwards. You could mount the accelerometer on a rocket and adjust it to stay at the same altitude and it would give the same reading.- (User) Wolfkeeper (Talk) 20:19, 16 January 2009 (UTC)
Unfortunately for you I have actually studied advanced physics including quantum electrodynamics and I believe I actually have an entirely adequate understanding of relativity, curved space, geodesics, simultaneity for the purposes of this article etc. etc. My favourite paradigm of quantum theory is the many worlds theory, as supported by Feynman, and no, I don't understand it any more than he does (OK, less.) Any questions? Oh, and you might like to mention that you are assuming GR theory in the introduction since otherwise it makes absolutely no sense, most readers will probably assume you are talking about Newtonian mechanics since you aren't mentioning curved space-time, and there is also the sticky question of the likely readers not actually being up on GR, and the introduction actually deceptively implying things that aren't true if they don't realise that.- (User) Wolfkeeper (Talk) 19:40, 16 January 2009 (UTC)
FWIW give me any more of this shit and I will simply revert the article. Unverifiable content can be removed at *any* time, and you've just added a whole bunch, and no references. Have a nice day.- (User) Wolfkeeper (Talk) 19:40, 16 January 2009 (UTC)
I just got a message on my talk from some guys working on WP:DICK apparently they want to do a feature article on you Greg_L; are you interested? They seem really, really keen.- (User) Wolfkeeper (Talk) 20:02, 16 January 2009 (UTC)
  • I have amply demonstrated above that the standard, world-wide practice amongst all manufacturers and distributors of accelerometers and as universally observed by scientific and medical researchers, and by NASA (which you poo-pooed as being “American”) and by the Europan Space Agency (all of these have been cited above), you roman lowercase g for the unit symbol g. You may not simply choose to ignore this when the article states as follows: “The gee is precisely equal to 980.665 gal. The world-wide standard practice has the unit symbol g as lowercase and roman (upright).” This is indisputably true. Stop editwarring. If you want to prove that the world-wide, standard practice is to use italic g, prove it. There also seems to be a chronic problem with your propensity to nebulously cite sources (such as the Canadian government manual of style) only to have other editors find it on Google Book and prove that it says no such thing. Wikipedia can’t work when editors operate this way. Greg L (talk) 20:18, 16 January 2009 (UTC)
  • As for your above allegation that I just got a message on my talk from some guys working on WP:DICK apparently they want to do a feature article on you Greg_L; are you interested? They seem really, really keen., that appears to be a lie. I just checked the history of your talk page. There is no record I can find of someone who is working on WP:DICK complaining about my behavior. All I could find on your talk is this recent complaint about your editwarring here. And I also see there is this recent complaint about your editing against consensus. Note also our proving that your supposed “citation” to the Canadian government manual of style was either a purposeful fabrication or an error. All in all, I’m seeing an extremely troubling pattern here with you. Greg L (talk) 20:33, 16 January 2009 (UTC)
Really? It's not there? I guess the admins must have deleted it or something; they can do so. Oh well. On the Canadian manual of style I was lead to believe that it stated that, but I did not have it to hand to verify. The Sutton book I did have, and I was able to show that it did indeed support the usage. Your comments which suggest a shaky understanding of the physics of accelerometers and g-force and your idea that you don't need to cite are still giving me some cause for concern though, but would not necessarily indicate a poor outcome. To be honest I'm glad to see someone enthusiastic about this article, although your attitude to your fellow editors could do with some... adjustment I feel.- (User) Wolfkeeper (Talk) 20:57, 16 January 2009 (UTC)

Wrong with the ESA you should look at the hires picture left side, g italic so what? This lemma is shure not GA. Internet and Google is the wrong place for the recherche for the Italic question. Better sources a physics books for university, only this is the standard. Fact is g can confused with g. Then for mathematical loosers, between digit and g is no space or you need a multiplication sign! --HDP (talk) 20:42, 16 January 2009 (UTC)

Then is gal obsolete and should not used! Gal is as unit outdated! Only earth sciences use gal.--HDP (talk) 20:49, 16 January 2009 (UTC)
  • “Obsolete”? Wrong again. Since 1978, the BIPM has approved the gal for use with the SI. Please note that the BIPM has also done this with other non-SI units such as gauss, tonne, liter, hour, and minute. (BIPM, Table 6 and BIPM, Table 9). Odd—that apparently “obsolete” unit, gauss; my company just bought a magnetometer a few months ago. It is calibrated in gauss. Note too my autosignature at the end of this post, which contains hours and minutes; units that are also not officially part of the SI but are recognized as acceptable for use with the SI. The gal certainly has good company. Greg L (talk) 00:08, 17 January 2009 (UTC)

The gal is not part of the International System of Units! [6]

    • I made some edits to the article before reading this. It's clear you are having a disagreement; are you able to state concisely what the exact nature of the disagreement is? I may be able to help as I'm also science-trained and have an interest in aviation, which often uses the unit. --John (talk) 06:26, 17 January 2009 (UTC)
  • Hallelujah. Semper Fi. Welcome. And an admin too!

    Per a recent post on my talk page (∆ here), Wolfkeeper might no longer respond here. But, in a nutshell, he has been arguing that g-force is not a measure of acceleration per se, it is the measure of inertial accelerations and ignores the effect of gravity. Specifically, he wrote in an edit comment while adding a {fact} tag as follows: g-force isn't actually a measure of acceleration, it's acceleration relative to gravitation field and then expanded upon it here on this talk page by writing I'm sitting at 1g but my acceleration is zero. Acceleration is m/s^2; m/s = zero. I know. But he wrote above that I have actually studied advanced physics including quantum electrodynamics.

    He has also been arguing that g is supposed to be italicized in order to avoid confusion with the symbol for gram. Perhaps that ought to be the case. But it isn’t. Further, the basis for making this claim hadn’t been cited since this article first began—for years; the “citation” was only alluded to here on the talk pages as being advise from a Canadian government manual of style. When challenged recently, he cited the manual of style (here) and the publishing house, but couldn’t quote the text or page when repeatedly asked. It was finally shown via Google Book search (Hipocrite (talk) 20:34, 14 January 2009 post) that the manual says no such thing. I think my litany of citations are sufficiently authoritative to buttress the obvious.

    I’ll be wading into this article over the weekend; it needs work. Your assistance here will be quite welcome. Thanks for the “trim”. Greg L (talk) 07:29, 17 January 2009 (UTC)

I'am a Dipl.Ing and not nowdays common lowcost master ing. --HDP (talk) 07:28, 17 January 2009 (UTC)

gn v.s. g

They are two different things. The symbol for standard gravity is gn. One g, as it applies to g-forces, is equal to gn. This is all cited in the article. Greg L (talk) 23:19, 16 January 2009 (UTC)

Notation: variablen and constants writen always kursiv = italic point 2 [7]Maybe a little bit to high for some here, from an Experimental Physics book. g = gE-Ω2*R that is the effective gravity Experimental Physik 3.194, 3.197, 3.199. That shown gE and g must writen italic in context! That indicate that NASA and ESA use a non standard notation! --HDP (talk) 11:25, 17 January 2009 (UTC)

No, one is a quantity and one is an unit. You can write mu = m(12C)/12 and that would be an equation about quantities, but this doesn't mean that the unit isn't 1 u (see atomic mass unit). I don't know about this particolar unit, the gee, but "That shown" and "That indicate" are non sequiturs. -- Army1987 – Deeds, not words. 16:59, 17 January 2009 (UTC)
  • Precisely. Let’s take it as an article of faith that NASA, ESA, and JPL, which are all heavily populated by scientists with advanced degrees and Ph.D.s, actually know what they are talking about. Let’s also acknowledge that Honeywell [8], a world-wide, leading manufacturer of industrial and military-grade accelerometers, knows what they are doing.

    This is not complex. My younger brother is a pilot and I subscribe to Aviation Week & Space Technology, which is the preeminent periodical for the industry. It contains advertisements for missile defense systems, commercial launch services, and fighter planes. It is subscribed to by industry and government leaders throughout the world. They write “a 9 g turn”.

    There will never be a way for me to prove it—and I certainly might be wrong about this—but I will forever suspect that at least some of the editors responsible for this knew full well that the standard practice observed throughout the world is roman g, but they simply believed the practice unwise and hoped to promote change in the way the world works by stating a falsehood as a fact.

    The only people who were writing “a 3 g roller coaster” were school children who had the misfortune of landing here and being exposed to misinformation. Now fixed. Greg L (talk) 21:18, 17 January 2009 (UTC)

  • I certainly confirm that all the aviation magazines I read and all the books, as far as I can recall, use regular upright g to show g-forces. I can see the argument for using g to avoid confusion, and it may well be done that way in some physics books, but I think we should always follow the sources. On a completely other note, I know the RAF call their anti-g garment their "turning trousers"; if I can reference that I may try to add it to the article. --John (talk) 04:21, 18 January 2009 (UTC)

Inappropriate tone

The chatty style of the first two sections -- "Understanding the nature of the measure" and "Gravitational and inertial acceleration" -- is inappropriate for an encyclopedia article. —Preceding unsigned comment added by 86.134.30.255 (talk) 04:54, 18 January 2009 (UTC)

  • Agreed. I questioned whether the “Why?” was encyclopedic when I wrote it. Now fixed. I’m not really seeing anything else. So, I.P. editor from London, please be specific about any remaining un-encyclopedic passages you feel still need to be addressed. Greg L (talk) 04:58, 18 January 2009 (UTC)
  • Yeah, agreed doubly. I made the edits (again!) before reading this, but I hope they go some way to alleviating your concerns. Specific suggestions are always especially welcome here, as Greg says. --John (talk) 05:22, 18 January 2009 (UTC)

g-force trivia

What are we to do with G-force#Human_g-force_experience. It reads like a trivia section and is a citation nightmare. An editor today put a {fact} tag on an assertion that a wristwatch is rated for shock of up to 7 g. So I checked into it and found that watches are rated for shocks of 5000–7500 g. What a colossal goof. That was just one item and it took a fair amount of time to dig up the facts. I could abandon the article now, but my style is to stick with these things to the end. I think much of the stuff—and there is a lot of it—in this lower half of the article could be made much more succinct and tied together better. Who here is married to all those bullet points? Greg L (talk) 04:57, 18 January 2009 (UTC)

  • Agreed. Bullet points are fine for multiple comments in talk (as here), but they make the article look bad. Put it into prose, keep that which can be verified (I'm not against having a few interesting g-based data points on an article about g-force), and lose the rest. Onwards and upwards. It's already looking better, I think. --John (talk) 05:28, 18 January 2009 (UTC)
    • However, on reflection, the whole latter part of the article is avoidably scrappy. As the article makes clear, transient g-forces (a slap or a sneeze) are inherently more survivable than sustained forces. We need to rewrite the entire thing in a more coherent way, and we need to make any claims of "records" especially well referenced, or we shouldn't be making them. Just my opinion of course. --John (talk) 06:00, 18 January 2009 (UTC)
  • I’m not sure what to do. Excising material is bound to be particularly painful to whoever put it there. However, the majority of the “records” and “greatest ever”s are un-cited. Nor are most of them really needed. Furthermore, this article looks a lot like the Guiness Book of World Records and it’s not supposed to. An encyclopedic treatment of g-force can be thoroughly covered here by touching briefly on a handful of particularly notable special conditions. We could, for instance, do a better job here by touching upon the rate of change of acceleration, which elevator engineers call “jerk”, instead of messing around with what looks like a list of every roller coaster on the planet. As you pointed out, we can continue on with a brief discussion of transient effects. Note too, that this article has a table of NASA g tolerance data, but it would be better if this data was simply an external link in a Further reading section.

    As is typical when I’m in this situation, I’ll probably just add another section, copying from what’s here at times, and afterwards, simply delete redundant and unnecessary sections. That whole Human g-force experience is completely out of hand. Besides, a big list of roller coaster peak g-forces begs to be its own article; it may well be a separate article already. Greg L (talk) 09:04, 18 January 2009 (UTC)

Yes, the bragging list of roller coaster rides belongs in Roller coaster. This article does need a good thorough review and clean up. Rlsheehan (talk) 16:42, 18 January 2009 (UTC)
Yes, I agree and have tagged some with a view to removing them if they can't be reliably sourced. See also the new section below. --John (talk) 18:08, 18 January 2009 (UTC)

Yoke

I only linked it as it's not that common a word and many people wouldn't know it. How about changing it to "control column" or "joystick"? Probably the latter. I do agree with the sentiment of not having loads of distracting links. --John (talk) 05:30, 18 January 2009 (UTC)

  • Or just “stick”. Any of the three. Your choice based on what you think will be most universally understood without linking. I’ll go ahead and try stick. Change to something better if you like. Thanks for my second “trim.” Greg L (talk) 05:37, 18 January 2009 (UTC)
  • Thanks again for the second “trim” and tone change. I could see the conversational tone, but couldn’t for the life of me figure out a way to purge it. Greg L (talk) 06:02, 18 January 2009 (UTC)

Highest g-forces survived by humans

This entire section has a fundamental problem. Transient g-forces are much more survivable than prolonged ones. Is there a standard for defining "transient" vs "prolonged"? The airline industry uses dummies to test new designs of seats. Perhaps some of this section belongs in a different article; as it stands it contradicts correct information above it in the article. --John (talk) 18:11, 18 January 2009 (UTC)

  • Beyond the Black Box: the Forensics of Airplane Crashes by George Bibel, John Hopkins University Press, 2008 (ISBN 0-8018-8631-7) has a whole chapter on "Human Tolerance to G Loads and Crash Forces". I'll try to add some stuff from it later today. --John (talk) 19:09, 18 January 2009 (UTC)
    • I made some major trims, and changed a couple of things around. We don't need a bragging list, as someone said above. The source I quote was based on a survey of over 100 rollercoasters and seems reliable. Please see what you think. --John (talk) 03:19, 19 January 2009 (UTC)
Transient short-term "g-forces" are better described in the article on Shock (mechanics). Rlsheehan (talk) 03:34, 19 January 2009 (UTC)
Nice trims, Greg. I restored my reference with the figure 3.5 to 5 g, based on an extensive survey of rollercoasters and in a serious book about aviation safety. It looks so much better with that one sober reference than with all these supposed bests. --John (talk) 04:19, 19 January 2009 (UTC)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Talk:G-force/Archive_1&oldid=1077501935"