Talk:Centrifugal force (rotating reference frame)

Don't revert removal of xkcd links

You need to give a reason for putting xkcd links in an article. Wikipedia isn't an xkcd fan-site. WeDon'tWantAny (talk) 07:34, 5 December 2009 (UTC)

The use of cartoons like this to illustrate difficult topics has a long history in physics. As it happens whether this should be included or not, this question came up before, and the decision was that we actually want to include the cartoon in the article if at all possible. The cartoon is after all, technically accurate and penned by a professional physicist.- Wolfkeeper 13:55, 5 December 2009 (UTC)

Please find the discussion for reference. Until then the link stays out of the article. I don't buy your reasoning (the comic explains nothing to the reader, and is simply an in-joke for people to feel pleased about getting). However, if you truly believe what you're saying, I'm sure you'll be happy to see the xkcd comic replaced with something I've scribbled on a piece of paper (it's a comic featuring stick-men explaining the principles of centrifugal forces). Being completely neutral about xkcd I'm sure you will be happy to see this included. WeDon'tWantAny (talk) 17:35, 5 December 2009 (UTC)

Feel free to scribble stuff and upload, and I'm sure we'll treat it according to its applicability to the article. In the meantime the XKCD cartoon is actually notable in this context.- Wolfkeeper 17:49, 5 December 2009 (UTC)

Ridiculous, you even say yourself that the comic will probably get removed because of tone in that original discussion. Why not run with that feeling instead of rabidly defending its inclusion because *you like it*? WeDon'tWantAny (talk) 22:32, 5 December 2009 (UTC)

The cartoon is on topic and entirely appropriate and to the point; indeed I want it in the article and this was agree by the other editors, and the only reason it isn't is because we haven't been able to negotiate a license. If you read the WP:EL guidelines, you'll find that makes it eligible for inclusion in the external links section; we are allowed to include references to things we are not able to include- that is correct linkage.- Wolfkeeper 22:40, 5 December 2009 (UTC)

By that same token, I could point out that your link matches the profile of "Links normally to be avoided"; see points 1, 13 and possibly 11. WeDon'tWantAny (talk) 22:57, 5 December 2009 (UTC)

Not a single one of those applies. 1- it actually is a unique reference. 11-It is not a blog, personal page (it's actually a commercial page) nor a fansite. 13- this particular link is directly related to the subject of the article.- Wolfkeeper 17:06, 7 August 2010 (UTC)

At the moment there are license issues, I did send a request to the copyright owner to see if he would agree to relicense it; I never got a reply, but I may ask this again though; apparently he gets swamped with emails, so he may not have read it.- Wolfkeeper 13:55, 5 December 2009 (UTC)

If it's something that we'd like to include in the article, but can't due to licensing issues, then that's what external links are for. Dicklyon (talk) 08:17, 6 December 2009 (UTC)

RfC: Does a link to a web-comic belong in this article

Does a link to a web-comic that references the article material warrant inclusion in the article? WeDon'tWantAny (talk) 22:54, 5 December 2009 (UTC)

Looking at the last version with it in I would say include it: it does illustrate the common (mis)understanding of the term. But it doesn't need a cute title. Something like "XKCD comic 123" is all that's needed. Those who want to be entertained, or find out what xkcd is, can follow the link. JohnBlackburne (talk) 23:53, 5 December 2009 (UTC)

• Keep - While it is a 'webcomic' it's written by a professional physicist, is about physics, the cartoon is technically accurate and illustrates in a fun way the physics involved. I'm not hung up on the title, but it needs to describe in some sense what the link does for the user.- Wolfkeeper 02:14, 6 December 2009 (UTC)
• Keep xkcd offers a unique, often humorous view of physics topics we cannot easily integrate into an encyclopedia article. -Atmoz (talk) 02:38, 6 December 2009 (UTC)
• Remove I'm a fan of xkcd and the comic is entertaining, but it has as much to do with Goldfinger as with Centrifugal force. The criteria for inclusion of external links are pretty clearly spelled out in WP:EL and while it may be fun, the strip is does not have information that is not already in the article, nor does it constitute a unique resource. It's would tempting to link to many of the xkcd strips from corresponding wikipedia articles, but it's not encyclopedic to do so.--RDBury (talk) 04:05, 6 December 2009 (UTC)

• On the contrary, we've found in the past that pointing people who were working on the article to it immediately reduced the arguments about the topic. It's a unique resource because the artist managed to get the key parts of whether 'centrifugal force' is "real" or not into just 4 small pictures and a tiny bit of text; and it's unique resource because it's copyrighted, and cannot be easily duplicated.- Wolfkeeper 15:37, 6 December 2009 (UTC)

• Remove Ditto RDBury. While it may possibly expose the misconception, that's not an adequate reason to have it linked per WP:EL. --Izno (talk) 05:58, 6 December 2009 (UTC)
• Keep - It's a decent illustration of a common misperception. That's an excellent reason to include the graphic. The external link is optional IMO... Yes, people can google XKCD for themselves, but why not save them a few clicks? That's the purpose of a hyperlink anyway, right? Plvekamp (talk) 06:15, 6 December 2009 (UTC)
• Keep - the web comic is a valuable illustration of the concepts discussed in the artile. It is a "unique" resource in the sense of providing an accessible illustrating of the crux of the confusions in this area. A link to it seems appropriate. Dicklyon (talk) 08:15, 6 December 2009 (UTC)
• Remove - The comic is fancruft. It doesn't serve to explain the confusion about centripetal and centrifugal forces because the comic requires you to know this in the first place in order to appreciate the joke. It could easily be replaced by one of many other sources. WeDon'tWantAny (talk) 08:33, 6 December 2009 (UTC)

• I haven't found that to be the case at all; you can point people to other sources as much as you want; but it's a rare case of where the maxim "a picture is worth a thousand words" is really true.- Wolfkeeper 15:39, 6 December 2009 (UTC)

I think it's more a case of "I like xkcd and I want to keep it in the article". I really don't see how it is defensible. It's not reference material, its value is highly dependent on point of view, and it's not Wikipedia's responsibility to enrich people's lives with popular culture references. This should be discouraged as much as possible, otherwise we would end up with xkcd in every science article, as the comic's formula is making references to science topics. If you take your reasoning out of context you must see how ridiculous it is; by the same logic I should be adding "why did the chicken cross the road?" jokes to the Chicken article, to "illustrate the hazards of chickens in urban environments in an accessible way". As a side note, please don't tally up the votes from an RFC merely hours after it is opened and when no consensus is reached. The point of RFCs is not to "win votes", but to help people come to an agreement about content. WeDon'tWantAny (talk) 16:32, 6 December 2009 (UTC)

Your point is both a facile view of the issue and deliberately deceptive, since 'why did the chicken cross the road jokes' are not really about chickens in any material way. It seems to me that the difference between 'cruft' and non 'cruft' is whether the material is really on-topic or not. In this case it really, is on topic; it really is about the difference between centrifugal force as a completely fictitious concept and something that appears in the equations and represents something that is real enough that it can actually kill you. In this way it adds to the topic, as opposed to adding to the subject of the cruft. If you really can't tell the difference, I would strongly recommend you not write any more for the Wikipedia.- Wolfkeeper 16:45, 6 December 2009 (UTC)

We could both keep moving the goalposts on this until the end of time, but that wouldn't change Wikipedia's actual policies, which have been laid out for you by three editors now. I suggest you read what the other pro-removal people have said and try to take it in objectively. Pretend it isn't about xkcd, but something you don't hold dear to your heart instead (as RDBury did). As you're now telling people that they probably shouldn't be editing Wikipedia when their views differ from yours, I think you should probably step away from this issue until you have regained your cool. WeDon'tWantAny (talk) 16:57, 6 December 2009 (UTC)

The only goalposts are the policies, and they aren't especially movable. If you believe this violates a policy, you will have to quote it for us; as I'm pretty sure there is no violation here; nothing you has said so far identifies any policy violation at all.- Wolfkeeper 00:44, 7 December 2009 (UTC)

WeDon'tWantAny : You asked for comment; you're getting it. This assumption that anyone who disagrees with removing the link must be a fan of XKCD is erroneous. I, for one, am no fan; I think most of his cartoons are banal and barely amusing. This particular one is on-topic and quite illustrative. If we can get a copyright release, I think we should include the graphic itself in the article. I note that the only edits you've made to the Wiki are for the purpose of removing XKCD links... Have you read WP:SPA? Plvekamp (talk) 17:19, 6 December 2009 (UTC)

I'm not sure where I complained about comments being made. Could you please quote the text that implied this? I did complain about being rudely told that I probably shouldn't be editing Wikipedia, but that is not the same thing! Please read my talk page where I explain that I have simply noticed a lot of xkcd links that don't belong, and have been removing them. If you want to make accusations about my motives please go through an more appropriate channel where you can justify your reasons for doing so (such as getting the behaviour stopped), as otherwise it just looks like a snide attack. This is a RFC about the article, not about a user. I do see that I shouldn't be adding "mission statements" to my user page, so thanks for pointing that out. I wrote that I am removing inappropriate links from Wikipedia as an explanation of what I am currently doing per my routine, not to lay out a singular goal. If I have to suffer criticism for removing an easily identifiable body of cruft in a short space of time, so be it! WeDon'tWantAny (talk) 17:35, 6 December 2009 (UTC)

• Remove: fanboy cruft. 86.153.8.118 (talk) 16:15, 6 December 2009 (UTC)
• Keep, I can't think of a valid reason to remove it.Chhe (talk) 19:21, 7 December 2009 (UTC)

Wikipedia:Xkcd_in_popular_culture#Inappropriate_references —Preceding unsigned comment added by 90.215.124.158 (talk) 19:23, 13 December 2009 (UTC)

Well, if the license is ever compatible, I have no intention of adding it as popular culture, nor is it there now; it will be a proper diagram that is part of the text.- Wolfkeeper 22:25, 13 December 2009 (UTC)

• Remove. The comic is funny for someone who is familiar with the quasi-controversy it refers to, but it adds essentially no encyclopedic value. (Funny is not an encyclopedic value). If it had a compatible licence, I would support it as an inline image -- but that is different from an external link. –Henning Makholm (talk) 23:39, 13 December 2009 (UTC)

• Remove: The comic doesn't seem necessary and the website is commercial (sells the comic). TheGoodLocust (talk) 21:50, 27 December 2009 (UTC)

Can you–in good conscience and without trying to twist reality–explain how the strip satisfies points 1-3 in this section?90.215.124.158 (talk) 18:11, 1 January 2010 (UTC)

That section is neither guideline nor policy; it is only an essay. You cannot claim it as authoritative. The comic illustrates a concept quite well in this article. Considering your incivil edit summary towards me ("grow a pair of balls, get cancer in them"), along with your contribution history, I'd suggest your apparent obsession on this issue is prejudicial against the case you're trying to make. Plvekamp (talk) 19:52, 1 January 2010 (UTC)

Yes, but WP:ELNO#11 is guideline. What xkcd in pop culture does is explain when ELNO#11 is best to apply w.r.t. xkcd. If you can make a case against the three points that the IP makes, then you may have legitimate reasoning to keep the link. --Izno (talk) 20:12, 1 January 2010 (UTC)

WP:ELNO#11 reads: 11. Links to blogs, personal web pages and most fansites, except those written by a recognized authority. This link is not a blog, personal web page, or fansite. It is simply a comic. Wikipedia:Xkcd in popular culture is an essay against indiscriminate spamming of xkcd into articles; this particular case is not spam, and the essay is not applicable. Further, this section of WP:ELYES item 3 reads:

What should be linked

3. Sites that contain neutral and accurate material that cannot be integrated into the Wikipedia article due to copyright issues, amount of detail (such as professional athlete statistics, movie or television credits, interview transcripts, or online textbooks) or other reasons.

This xkcd graphic, as noted above by several editors, cannot be integrated into the article due to a copyright issue. It is therefore incorporated as an external link according to this guideline. Several editors of this article with professional knowledge of the subject have expressed value for it above. Plvekamp (talk) 03:42, 2 January 2010 (UTC)

1) Its supposed value is entirely POV. Editors with professional knowledge of the field aren't the same thing as reliable outside sources 2) Not being a blog, fansite or personal web page (and you have purposely taken a narrow view of this criteria) doesn't mean that comics are fine. The page doesn't give extra information on the topic and it's not written by a recognised authority. 3) Why isn't it spam? Why do the rules not apply to this comic? Why is "it can't be embedded and so it is a valid external link" valid reasoning (you've twisted that guideline for your own purposes; it's only there for things that should be embedded content, and this most certainly shouldn't be)? Why do you think those three points you were asked to satisfy aren't a valid condensed form of the linking guidelines and why do you refuse to answer them?

It's important not to let Wikipedia get bunged up with things just because people like them. Go read an article about vampires and imagine if an excerpt from Twilight was added because somebody claimed it helped people understand the concepts, even though it obviously didn't. Would you be happy to see that stay? xkcd is no more golden than Twilight, and shouldn't be given preference in Wikipedia articles the way it is. Many people are of the viewpoint that xkcd's writing process involves the author scanning Wikipedia for concepts that will appeal to its fanbase and then basing comics around them in order to pander to them. We don't need this being fed back into Wikipedia. It's not a reliable source. 90.215.124.140 (talk) 09:35, 2 January 2010 (UTC)

Furthermore, have you thought about the precedent you would be setting? Can I now go and scour the Internet for my favourite comics that reference a subject and add those under the pretense that it makes the subject matter easier to understand, or is this just a special case for comics you like? You can't have a special rule for one thing. xkcd's entire basis is referencing scientific topics. If your addition is valid then we'll end up with xkcd on far too many pages, and it would be ridiculous and selfish. 90.215.124.140 (talk) 09:54, 2 January 2010 (UTC)

You evidently didn't read my comments above. I said, "I, for one, am no fan; I think most of his cartoons are banal and barely amusing. This particular one is on-topic and quite illustrative. If we can get a copyright release, I think we should include the graphic itself in the article." An external link is a reasonable alternative to an embedded image, by guideline. This is not an "xkcd in popular culture"-type use; it is an "xkcd gives a useful image"-type use. I'm not about to go spamming links into any articles. Worries about precedent-setting are a bit paranoid, in my opinion.

Also, thanks for calming down the vitriol, and stating your reasons calmly. We may disagree, but at least now I can understand the motivation for your opinion. WP:CIVIL is just as important as WP:EL; probably more so. Plvekamp (talk) 17:43, 2 January 2010 (UTC)

Could you stop putting the link back in with the edit summary "per talk", as if a consensus has been reached? I can't help but feel that you are trolling or trying to pull the wool over people's eyes with that one. You can't say "per talk" when an agreement clearly hasn't been reached!

If you let the xkcd link in then why should any other editor feel like they can't just add anything they've taken a liking to? And the question remains, how does this comic satisfy WP:EL? You *personally like the comic*; I really feel that this is the only reason anybody would keep it. Again, how does the link satisfy the the guidelines? It needs to do better than being "descriptive" (I don't believe it is even that). It needs to give information and to be a source of knowledge, not just to reference something that the article is about. This is supposed to be a repository of information, not an accessible, chummy textbook with little cartoons to keep students happy in class. 90.217.104.238 (talk) 19:39, 2 January 2010 (UTC)

And could you also stop removing the link, as if a consensus has been reached ? This is a tiresome argument. I personally do not like the comic, in general, only this one particular use, and most editors with knowledge of the subject have agreed with keeping it. An image is worth a thousand words, as the saying goes. I have no agenda, as some apparently do, I simply think this image is an improvement to the article. I won't edit-war; if someone else wants to put the link back in, great. If no-one else puts it back in, then perhaps the image isn't as valuable as I thought. Either way, I'm fine with it. Let consensus be shown by actions. Plvekamp (talk) 19:53, 2 January 2010 (UTC)

• Keep. It is a very good example, and I believe it can engage many readers to re-read (and actually understand :) the article. As has been said above, it would have been a great illustration for the article if it could have been included. PS! it is always useful to provide the link being discussed so non-involved editors can quickly understand what it being discussed, so here is the link to the comic: [1] Labongo (talk) 08:10, 2 January 2010 (UTC)
• Keep. Astute, to the point and highly on-topic. DVdm (talk) 21:57, 2 January 2010 (UTC)

---

I don't believe the link is appropriate in the article; it's just a joke related to the article's topic. (It might come under #13 of the WP:EL counter-examples.) What other articles should have XKCD comics linked? (I know of one page where it would have been just as relevant, but for obvious reasons I won't link it here.) I don't want to be revert-warring, so take my edit and this message as just my opinion, I won't press it any further. - Mike Rosoft (talk) 20:29, 8 January 2010 (UTC)

There isn't much consensus for this (although I do respect your opinion). We would really much rather have the graphic image on the page instead of a link; I think most of the editors above agree it does help illustrate the difference between centrifugal and centripetal force. Without license to include it, however, we've deep linked to the graphic. Indeed, the last sentence of #13 says: "If a section of a general website is devoted to the subject of the article, and meets the other criteria for linking, then that part of the site could be deep linked." The intent was certainly not to spam XKCD, and thank you for not accusing anyone of such. Your civility is appreciated!! Plvekamp (talk) 22:43, 8 January 2010 (UTC)

• As the actual author of WP:XKCD, I'd say that it's more than applicable here. The comic is hardly the best way to represent what little descriptive material it has on centrifugal force; it most certainly does not "provide unique value to the article beyond that which the article would contain itself at FA class" (contrary to the gainsaying above). As such, it fails to meet the inclusion criteria at WP:EL, and people don't get to override that by a show of hands. I'll be removing this again in a couple of days, and if I see it being reverted back using popups in by editors who should know better (you know who you are) then I'll be taking it to the edit warring noticeboard. Chris Cunningham (not at work) - talk 14:19, 26 January 2010 (UTC)
• Remove I'm here from ELN. I've dealt with a lot of EL issues, and this one is pretty obvious. I'm really suprised at all the non-policy-based "keep" opinions here since this link should most definitely be removed as per our WP:EL guidelines. It doesn't contribute to an encyclopedic understanding of centrifugal force at all, so it fails WP:ELNO point 1 which reads that Any site that does not provide a unique resource beyond what the article would contain if it became a featured article. should be avoided. The site also isn't very informative about the subject matter, it's just a joke, so it fails WP:ELYES as it doesn't provide an encyclopedic understanding of the subject (don't get me wrong, I love xkcd, but its really not acceptible for linking unless the subject matter in the article directly relates to the comic strip). ThemFromSpace 05:07, 4 February 2010 (UTC)
• Remove. I am responding to the notice at WP:ELN. While IMO the link is not actually prohibited by WP:EL (thousands and thousands of links are not actually prohibited by WP:EL), although I understand the WP:ELNO #1 concerns that several editors have expressed, it does not add to my understanding any more than a single, plain sentence would. That is, as a non-specialist who has read (only) the comic and the lead, I learned nothing about centrifugal force from the comic that I didn't know after reading the lead to the article. It's cute, it's succinct, it's memorable, and it's kind of funny (and, oddly enough, I'm wearing #552 today), but it doesn't strike me as either encyclopedic or really useful to the reader. I would remove the link. WhatamIdoing (talk) 03:21, 9 February 2010 (UTC)

Summary of arguments

So it seems that people are going to keep edit warring unless there's a definite conclusion here.

The arguments against including the comic are:

1. It's non-free. This means that it cannot be included in the body of the article, but only as an external link.
2. It does not provide unique value in explaining the subject. (There's a lot of gainsaying about this above; I find it disingenuous to suggest that one could not draw a diagram which explains the science just as well as the comic.)
3. The primary motivation behind its inclusion appears to be not that it clarifies the subject in a way that we could not do ourselves, but rather that it's amusing. This is not an argument grounded in our guidelines. Furthermore, the use of humour in articlespace is not generally in line with our guidelines on article tone.

If anyone wants to refute those points, be my guest. Chris Cunningham (not at work) - talk 10:28, 28 January 2010 (UTC)

1. As a matter of fact it is free. It's licensed with a non commercial GPL license; unfortunately it's incompatible with the Wikipedia's license.
2. It's funny, which a 'diagram to explain the science' is extremely likely not to be.
3. You do not appear to be assuming good faith. I added because it did actually clarify the subject, and I checked on the talk page here before adding it. I even tried to get it relicensed, but never got a reply from the author; I understand he has since declared email bankruptcy so it might be worth trying again.

- Wolfkeeper 23:58, 3 February 2010 (UTC)

1. CC-NC-SA isn't a "GPL" license; the GPL forbids non-commercial clauses as well. For Wikipedia's purposes it's non-free, even if it has additional rights beyond fair use. Were it to be available under CC-BY-SA then we could have it on Commons; as you say below, you've tried but haven't had any luck.
2. Humour should not be a factor in considering the desirability of links. This isn't Digg.
3. My characterisation of your motive for getting it included is exactly what you said in the response to point 2 above, so I can't see how I'm making assumptions which aren't correct.

Chris Cunningham (not at work) - talk 09:31, 4 February 2010 (UTC)

There's no policy about humour in the wikipedia at all, and ignoring the humour aspect in fact nobody has managed to come up with a diagram that is nearly as succinct or nearly as clear. At the very least, until that happens this is a unique resource.- Wolfkeeper 16:08, 4 February 2010 (UTC)

Anyway, this farce has gone on long enough; the poll has been running for almost exactly two months, normally RFCs run for just one month, and you've been totally unable to drum up enough 'cruft' deletionists to remove it, that alone should tell you something; in the meantime, this is an advanced physics article, and most of the editors with advanced physics support its presence. You have not been able to get consensus for its removal. It's time to close the poll.- Wolfkeeper 16:08, 4 February 2010 (UTC)

The comic's actual artwork is irrelevant to the explanation (which is contained entirely within the text of the second panel), so it could (and indeed has to be) explained in the article body. Head counting is a non-argument, and appeals to authority from pseudonymous editors are even less compelling. This is not a "poll": it's a discussion, and it would be best if someone who wasn't vociferously on one side or the other judged the outcome. Chris Cunningham (not at work) - talk 21:03, 4 February 2010 (UTC)

• It is made available under a CC licence so could be included: not that anyone is advocating that. The other points are much more subjective. I would say it does illustrate the different ways of thinking of it, in a way WP with its encyclopaedic writing style cannot, or at least cannot so easily. Subjective though I know. --JohnBlackburne^words_deeds 10:37, 28 January 2010 (UTC)

• Unfortunately, although it is a free license, it's the wrong license. I've requested the author relicense it for us. I really, really hope he does.- Wolfkeeper 16:08, 4 February 2010 (UTC)

• Edit warring was not really what I had in mind. I made a few remarks on my talk page. DVdm (talk) 10:43, 28 January 2010 (UTC)

• Comment: I've requested editors who hang around WP:External links/Noticeboard to see if they have an opinion to give, as it currently appears to me a deadlock now (with some edit warring around the edges). --Izno (talk) 01:07, 4 February 2010 (UTC)

Conclusion

It's been another week, and Wolfkeeper (talk · contribs) (who for some time has been the only editor strongly in favour of the link) has deleted the discussion on his talk page while declining to respond further here. I think at this point there's consensus that the link does not provide enough value to warrant inclusion. Chris Cunningham (not at work) - talk 10:23, 11 February 2010 (UTC)

I am strongly in favour of the link, and so are others. I think we're just not prepared to repeat our arguments sixteen times. There is no consensus for removal, so it should really stay where it was. DVdm (talk) 12:21, 11 February 2010 (UTC)

Your argument, quoted from above, was: "Astute, to the point and highly on-topic". This is no argument at all. I do wish people would also stop repeating the phrase "there is no consensus" as if it were an argument in itself. And the only reason you're being asked to repeat your arguments is that I'm not prepared to hit the undo button repeatedly when someone disagrees with me, which has thus far been the only reason this link has stayed on the page. Chris Cunningham (not at work) - talk 14:11, 11 February 2010 (UTC)

First, if you think that my comment was no argument at all, then perhaps I should have used "comment or vieuwpoint on the RFC with title Does_a_link_to_a_web-comic_belong_in_this_article?". So let me rephrase part of my previous reply as follows: I think we're just not prepared to repeat our comments or viewpoints on that RFC sixteen times.

Second, you stated that "...there's consensus that the link does not provide...". I don't think that there is such a consensus. That is not an argument, but a fact. Also note that if there is no consensus to change something (in casu removing a link), then generally the proposed change should not take place - at least I think I've read something along these lines in one of the guidelines or policies. DVdm (talk) 14:45, 11 February 2010 (UTC)

I'm prepared to accept that I was premature here, but that's what happens when people are prepared to edit war until they get their way and then stop contributing to talk until prodded again. I'm taking things slowly to try to avoid that. As for inertia taking precedence in argument like this, I would note that the link has been removed by over half a dozen different editors over the last year, which would hardly seem to indicate that it was a stable element in the first place. Chris Cunningham (not at work) - talk 14:52, 11 February 2010 (UTC)

For the record, I'm not prepared to editwar over anything. Furthermore, I think we can safely reduce this "over half a dozen different editors" to "a few editors", as it is clear that {90.220.88.171, 90.217.104.238, 90.215.124.158, 90.215.124.140, 90.214.85.123} belong to one and the same person. DVdm (talk) 15:06, 11 February 2010 (UTC)

Actually, it is only one shy of that figure even if you dismiss the IPs altogether, and you could include me if I didn't have the patience to sit through a discussion about it. Chris Cunningham (not at work) - talk 15:28, 11 February 2010 (UTC)

I'm also in favour. That you've not heard so for a long time is as this discussion has been going on for a long time and I've not seen the point in repeating myself, unless prompted to by something like this. My own view of the consensus is there's none, i.e. there have been contributions in support of both sides of the argument and no-one has really changed their views.--JohnBlackburne^words_deeds 14:21, 11 February 2010 (UTC)

It's not a matter of people "changing sides". Consensus does not mean taking the original argument and see who does and does not agree with it; it' a matter of making arguments for one's position, figuring out what parts of those arguments we do agree on and working from that. In this case, there are good arguments and significant precedent in the guidelines not for including this as an external link (and indeed both of the editors contributing in the survey by way of the post at WT:EL agreed with this), and there has been no counter-response to suggest that there isn't broad agreement with the points made. On the other hand, the only part of the keep argument which people generally agree with is that it's a funny comic. Chris Cunningham (not at work) - talk 14:44, 11 February 2010 (UTC)

No, the summary of the above discussion is that there's no consensus for it's removal. You can't polish a turd, you guys lost.- Wolfkeeper 02:41, 8 August 2010 (UTC)

I'm also in favor of keeping the xkcd link, and for the record, I never understood the objections against it. It's just a cartoon that happens to be very relevant to the article topic and the confusion that sometimes accompanies it. Dicklyon (talk) 04:52, 8 August 2010 (UTC)

There is no "losing" on Wikipedia, and anyone who thinks so is likely here simply to create a battleground atmosphere. That's hardly conducive to consensus. The default here is not to include the link (which is inline with WP:EL) if there's no consensus. You've now decided to re-add the link after the article has been stable without it for 6 months. That's half a damn year to decide that you want it back in the article, which is unacceptable behavior, and if I had half-a-mind, I'd report the edits for long-term edit warring. --Izno (talk) 05:03, 8 August 2010 (UTC)

Radians per second

I always end up forgetting whether the formula is in radians per second or revolutions per second. I'm pretty sure it is the former here, but I don't want to screw up. Can someone confirm this is true throughout the text - and please sprinkle those units liberally so that people feel more comfortable working the equations? Also, the examples given include some mathematics, but they don't come down to concrete answers. I think that if you want to include an example, you should include something familiar like rotation of the earth at the equator and work it out to a plain number for the force.

N.B. the actual value for that is 1/289 of gravitational force [2], but their derivation leaves something to be desired (force measured in feet?). But to use their numbers, the radius is 20926202 feet, the period of revolution is 86164 seconds, and pi is 3.1415926. So the angular velocity is 2pi radians/86164 seconds = 7.2921 x 10^-5 radians/second. The centripetal acceleration is the angular velocity squared times the radius = 5.3175 x 10^-9 radians²/second² * 20926202 = 0.11128 radians² feet/second². Now at this point radians, rather magically to the uninitiated, make their disappearance, leaving 0.11128 ft/s² acceleration. The force experienced is this number times the mass of the object in pound-masses., which can then be converted to pound-force by dividing by standard gravity 32.174 feet/second² = 0.0034585 pound-force (per pound-mass). (Perhaps a sane metric version should also be given, but if you can follow this you can follow that! ;) ) Wnt (talk) 00:12, 11 December 2009 (UTC)

It's mentioned in a footnote, which I've made clearer. I've also added a wikilink to angular velocity which explains it further, tidying up a few other things in that section at the same time. In general though units are not given as the formulae are independent of units. Even the units for angular velocity would be wrong if you chose to work in e.g. Tonnes, Miles and Hours (you would need radians/hour) but seconds are almost always used even in non-SI systems so I think it's OK.

As for adding a concrete example, this is not appropriate to Wikipedia , as per WP:NOTHOW. Especially in a long article like this where there are a lot of examples, all quite different, as it would needed worked examples for all of them to fully cover the topic. But that would make the article a lot longer and just dilute the mathematical content. You perhaps want to look on Wikihow to see if that covers the topic in the way you want, or if you can add it there. --JohnBlackburne (talk) 10:10, 11 December 2009 (UTC)

Well, the article says that living on Earth is living in a rotating frame of reference, so the example is already used - just not explained. And the working of this precise example is sourced; I think it's one of the most common such questions asked. By comparison, several other examples such as the whirling table and the skywriter are not very informative, and the one about centrifugal force of the Universe is just plain bizarre. Wnt (talk) 13:11, 11 December 2009 (UTC)

Oh, and it doesn't matter whether you use radians per hour or radians per second, because the point is that the acceleration and force value you come up with is denominated in those units. The reason why clarifying radians or revolutions is particularly important is that those units don't exit the formula in as obvious a way. Wnt (talk) 13:29, 11 December 2009 (UTC)

I've rewritten the planet shape section - the galaxy stuff was pretty odd and unsourced, and there's a well written section on orbits later on so that serves much better so I removed it. There was also some Newtonian mechanics which duplicated something further up so I moved the reference then removed it.

The reason radians does not need clarifying is the formulae only work with radians: any other rotation measure introduces a scale factor. The need of radians in mathematics is pretty fundamental, and is considered background knowledge similar to e.g. the cross product and second derivative used in this article. None of these are explained but they are linked to where it makes sense, and readers can follow the links, including the category links at the bottom, for more information.

The links I've added include some such as flattening and rotation period with data. But again in general Wikipedia is not the place for detailed calculations of this data. Better to give the more interesting results and leave calculations it up to the reader, or to other sites like Wikibooks.--JohnBlackburne (talk) 14:59, 11 December 2009 (UTC)

I don't believe Wikipedia should be "dumbed down", but when possible an article should try to get at least some of the basic concepts across to laypersons and grade school students. People don't actually need to know calculus or trigonometry to run the numbers through the basic equation or to understand the general concept. This is the appropriate place to explain that radians are necessary, and for that matter why radians are necessary. Wnt (talk) 17:19, 11 December 2009 (UTC)

The problem is there are a lot of things going on "behind the scenes" in the few lines of algebra here. E.g. the fact that acceleration is a second derivative, or that the cross product is used to get from Ω to the derivative of Q, or what the cross product is, or that the magnitude of the final term is mΩ²r. All of it is explained, but it's explained elsewhere. That's how an encyclopaedia works: it covers everything but not all in one place. To include all or a significant portion of that into this article would result in considerable duplication and make an already long article longer and more difficult to read (and edit!). --JohnBlackburne (talk) 18:23, 11 December 2009 (UTC)

Removed Parachutist section again

With this edit user Brews ohare (talk · contribs) restored the Parachutist section he added in the version of 16 May 2009. The section was deleted on 22 dec 2009 by Wnt (talk · contribs), because "it has one reference that doesn't seem to talk about parachutes.". So I have removed the section again per wp:NOR and wp:UNSOURCED. DVdm (talk) 18:08, 6 August 2010 (UTC)

This section was rewritten, and not the same as the earlier version. To suggest that a source referring to parachutes be provided is strange. The section is not about parachutes, per se, but about straight-line motions as seen in a rotating frame. The notion of a parachutist is immaterial, just give a concrete picture. An arbitrary object could be chosen instead, obviously. Of course, straight-line motions require zero net force. As there is always a centrifugal force in a rotating frame, that means an agency is required to counteract this force if straight-line motion is to occur. I fail to see any OR here, nor any need to refer to a source on parachutes. Brews ohare (talk) 18:24, 6 August 2010 (UTC)

If this is not OR, then it will be easy to provide one or more good sources for the entire section. Please do so. DVdm (talk) 18:28, 6 August 2010 (UTC)

Um, perhaps you could provide some guidance that would illuminate for me just what in this section is OR? As I have pointed out, the point is simply that straight-line motion requires zero net force. Also, that centrifugal force is present in a rotating frame. These items hardly require further sourcing. Perhaps you are having difficulty with the way it is explained. Please advise. Brews ohare (talk) 18:31, 6 August 2010 (UTC)

Same case as before with this on Redefinition of the metre in 1983. Provide a source and you're in business. And please have a look at WP:BRD. It is not WP:BRDRD.... DVdm (talk) 18:35, 6 August 2010 (UTC)

Not helpful, DVdm. I guess there is some problem in being straightforward. However, here is a source for you: “Suppose that an object moves along a straight line in a rotating frame of reference. To an outside observer in an inertial frame the object's path is curved – thus there must be some force acting on the object to maintain the straight line motion as viewed by the rotating observer.” I would assume you would be very happy to work with me to apply this observation to the example of the parachutist to avoid any impression that this example involves complex logic or extrapolating conclusions implying OR? IMO it is a rather simple application of this principle, simple because the general case involves an apparent velocity and hence a Coriolis force, while this example does not. Brews ohare (talk) 18:45, 6 August 2010 (UTC)

It is not up to me to be helpful. It is up to you to provide sources when challenged. The source you just provided is sufficient for the sentence you quoted. It is not sufficient for the lecture you are trying to insert into the article. You really should know that by now. DVdm (talk) 19:18, 6 August 2010 (UTC)

You want a source for the parachute example? Do you have any objections to the physics, or are you just wikilawyering? /Pieter Kuiper (talk) 19:53, 6 August 2010 (UTC)

Pieter, the only thing I have is an objection to an unsourced, originally researched lecture. Wikipedia is wp:NOTTEXTBOOK. DVdm (talk) 20:29, 6 August 2010 (UTC)

Hi DVdm: I'm sorry that this example does not strike you as a useful addition to the article. I think it is, because it provides the flip side of the dropping ball example, and as such illuminates the concepts.

An invitation to help make the example meet your objections is not to say it is your obligation to do so. What it is, is an invitation to collaborate on building an encyclopaedia.

This example is obviously not OR in any sense of the word, and you have not made any effort to explain in any way the origin of your assessment. The above source provides the principle behind the example. The mathematics is given in the first paragraph of the WP subsection. This example follows not only qualitatively, as presented, but mathematically if one wants to follow through the provided math. If you really think this is my own idea or a projected conclusion beyond the principles, it is a commentary upon your understanding, or maybe your capacities.

That seems implausible. Brews ohare (talk) 20:08, 6 August 2010 (UTC)

I think you are in the same situation as here and here. Consider adding another RFC. I have nothing to add to my (4 times repeated) comments. DVdm (talk) 20:29, 6 August 2010 (UTC)

OK; I have made an RfC. Brews ohare (talk) 21:01, 6 August 2010 (UTC)

RfC: Is the following example a useful contribution to Centrifugal force (rotating reference frame)?

Is the following example a useful addition to the subsection Apparent motion of stationary objects?

Objections have been raised regarding an example, suggesting that it is WP:OR. The example is provided at this link. Please comment upon its suitability and, if possible, provide suggestions for its improvement. Brews ohare (talk) 21:00, 6 August 2010 (UTC)

• Here is the example:

Descending bird

A bird moving vertically parallel to the axis of rotation in a rotating frame appears to spiral downward in the inertial frame. The bird begins the drop with a horizontal component of velocity the same as the target site. The left panel shows a downward view in the inertial frame. The rate of rotation |Ω| = ω is assumed constant in time.

As a contrast to the above example of the dropping ball, which follows a straight-line path in a stationary frame, let's look at the change in fictitious forces when the straight-line path is seen in a rotating frame, rather than one that is stationary. To be concrete, imagine a bird descending onto a carousel, represented as a rotating flat platform.

Let us suppose the bird is initially hovering vertically above the destination site on the rotating carousel below, and therefore traveling at the same speed as the target below. The bird therefore starts with the necessary speed tangential to its path (ωR) to track the destination site. The bird aims to land upon the point on the rotating carousel directly below the drop-off point at the time of starting to drop.

The figure shows the vertical straight-line path of descent seen in the rotating frame. The bird drops at constant speed, occupying successively the vertically aligned positions one, two, three. Because the bird has zero horizontal velocity from the viewpoint of the rotating observer on the carousel, there is no Coriolis force in this example. There is, however, a centrifugal force.

From the viewpoint of the stationary frame, however, the bird must descend downward on the spiral path shown in the figure because the target position on the carousel is rotating. The stationary observer sees a uniform circular motion of the bird when the spiral motion is projected downward, as in the left panel of the figure.

How do the observations from the stationary frame and the rotating frame compare?

The stationary observer and the observer on the rotating carousel agree that there is no vertical force involved: the bird travels vertically at constant speed.

However, the horizontal motion is seen differently by the two observers. The rotating observer has this view: there is always a centrifugal force in the rotating world. Without a exercising an opposing radial thrust, the bird would be carried away by this centrifugal force and land far off the mark. From the bird's viewpoint, trying to keep the target directly below, the same appears true: as it falls vertically, a steady thrust radially inward is necessary, just to hold a position directly above target.

However, the stationary observer looking at the motion in the horizontal plane at the left of the figure, sees a centripetal force at work, -m ω² R. This centripetal force is necessary to maintain the circular path. According to the stationary observer, the bird needs a thrust to provide this force. Without thrust, the bird follows the dashed vertical path in the left panel of the figure, obeying Newton's law of inertia.

Unlike the dropping ball case, where the fictitious Coriolis and centrifugal forces conspired together to produce no need for external agency, in this case they require intervention to achieve the trajectory. The basic rule is: if the inertial observer says a situation demands action, the fictitious forces of the rotational frame will lead the rotational observer to the same conclusion, albeit by a different mechanism.

References

Comments upon RfC

• Please add your comments below, beginning with an asterisk *. It should be noted that this example is not in a vacuum; the mathematical background and another example precede it in the subsection. Brews ohare (talk) 21:05, 6 August 2010 (UTC)

• The fact that "the mathematical background and another example precede it in the subsection", is precicely what makes this section WP:OR. This is not a routine calculation. This section might belong in a textbook or in a lecture, but wikipedia is WP:NOT the place for this. DVdm (talk) 21:15, 6 August 2010 (UTC)

To the contrary, this is a completely trivial consequence of the material presented immediately preceding. If you have a problem making this connection, please point out what changes would fix that. Brews ohare (talk) 21:52, 6 August 2010 (UTC)

It belongs in a textbook or in a set of lecture notes. This is a request for comments. It is not a request for arguing whether Brews should be allowed to ignore all rules. DVdm (talk) 09:07, 7 August 2010 (UTC)

• There are only sources for the first paragraph, and not even all of that. Where are the sources for the rest of it? And the second link doesn't work: it gives me a "You have either reached a page that is unavailable for viewing or reached your viewing limit for this book" message. As I've not looked at the book (and can still look at other pages) it must just be outside the range of pages available for preview.--JohnBlackburne^words_deeds 21:21, 6 August 2010 (UTC)

I changed the source to one that still has a Google books access. As pointed out above, there is no need for further sources given the immediately preceding material. If you feel more is necessary, please be specific. Brews ohare (talk) 21:52, 6 August 2010 (UTC)

Yes there is: see WP:OR which is very clear on this: everything should come from sources, especially such a long and involved section which goes far beyond routine calculations.--JohnBlackburne^words_deeds 22:06, 6 August 2010 (UTC)

In fact, the presentation is qualitative. If the section appears involved, that may be a question of either your understanding of the topic (I don't claim any insight into this matter) or a question of clarity of exposition (which you could help me with by pointing out items you find are not obvious and so require sources or a better description). IMO the whole example is very straightforward, contains no logical complexity, is adequately sourced, and simply makes the basic ideas concrete. If that isn't working for you, please provide some specific guidance. That way, evolution can happen. Otherwise, you are in the position of making objections with no real intent of being constructive. Brews ohare (talk) 22:18, 6 August 2010 (UTC)

The constructive advice is "find sources for it". That's how Wikipedia works, content if challenged requires reliable sources, as it made clear at WP:OR. An exception is made for routine calculations that are easily checked and editors can agree on, but the unsourced content above consists of far more than routine calculations.--JohnBlackburne^words_deeds 22:34, 6 August 2010 (UTC)

John, you say "find sources for it". That is too vague. What exactly do you need sources for? The word it referring to everything is not specific. My feeling is that you haven't read this entire article and don't understand the concepts. That can make this particular example hard to follow, but is not my fault, and sources won't help. Brews ohare (talk) 23:28, 6 August 2010 (UTC)

BTW, there are no so-called routine calculations here, in fact, there are no calculations. The entire discussion is qualitative, needs no math at all (although math can be used if you prefer it), and falls into the regime of English discourse. Brews ohare (talk) 23:34, 6 August 2010 (UTC)

• This is routine reasoning, but rather wordy for a -pedia. The sourcing requirement leads to invocations of somewhat absurd references, like the robotics text. /Pieter Kuiper (talk) 21:44, 6 August 2010 (UTC)

Yes, insistence on verbatim sourcing means you have to look in strange places. Probably the example could be shortened, but even at its present length, DVdm and Blackburne have trouble understanding it. They think it is OR. Brews ohare (talk) 21:52, 6 August 2010 (UTC)

• My primary concern is that the edit in question completely fails WP:NOTTEXTBOOK. Specifically, "It is not appropriate to create or edit articles that read as textbooks, with leading questions and systematic problem solutions as examples." IMO, the example appears to be more to instruct rather to inform. As others have said above, it is more appropriate for a lecture or textbook, but not for a WP article (perhaps it could be used at Wikiversity). I believe the current examples in the article are more than sufficient to inform (in fact I'd recommend removing one or two based on the same WP:NOT argument) the reader. --FyzixFighter (talk) 22:24, 6 August 2010 (UTC)

This objection is both more germane and more difficult to support. The theses are: (i) Other examples accomplish the same thing. Please indicate which examples do that. And (ii) The example instructs rather than informs. If that has a meaning, I'd say that this objection means the example serves to teach skills (like exercises to master the mechanical details) more than it serves to sharpen understanding of the concepts. I can believe that opinion may vary on that judgment. My own is that this example, by treating a straight-line motion in a rotating frame, the flip side to treating a straight-line motion in a stationary frame, shows the following: in this case, centrifugal force has to be physically counteracted by a thruster, illustrating how real it is to the parachutist; on the other hand, in the dropped ball example, the centrifugal and Coriolis forces join up to produce exactly no need for any action. That illustrates the two faces of the fictitious forces, and is illustrative of the concept, not simply a teaching of manipulative skills.

Should we ultimately disagree about the impact of this example upon understanding, I'd opine that there is no need to drop the example inasmuch as it does have explanatory value, whether or not it has other benefits. Brews ohare (talk) 22:46, 6 August 2010 (UTC)

• Excellent text with a very nice illustration! I don't see what the problem here is. Sources are not needed when explaining a previously treated concept using an example. Examples and derivations are exempt from being challenged on the grounds of OR simply from lacking direct sourcing, unless a reasonable case is made that there is, (or that there can reasonable be), something wrong with the text. Also whether or not this fails WP:NOTTEXTBOOK is a matter of taste. Some Wikipedia articles by consent do read very much like textbooks (many of the articles I contributed to are of that nature), so this is not a blanket rule. What you probably don't want to do is rewrite a good encyclopedic FA class article into a dry textbook text that would lead to the article dropping from FA Class right back to Start Class :). Count Iblis (talk) 23:44, 6 August 2010 (UTC)

• As explanatory examples go, a long-winded explanation about a parachutist with a thruster seems overly complicated and confusing. The style is sort of text-booky, yet not very clear. The illustration is packed with info, yet not very clear. It's typical of Brews to defend this kind of article-bloating material that he likes to make up, and since he got kicked off of speed of light, he's attacking other topics now. Seems like a bad idea. Dicklyon (talk) 04:53, 7 August 2010 (UTC)

• This section should not be added to the article, because it is wrong. A parachutist falling at constant speed towards the center of Earth does experience a Coriolis force in the frame rotating with Earth, unless he falls straigt to one of the poles. Not over the poles his velocity is not parallel to rotation axis, and there will a Coriolis force East. This is called the Eötvös effect. −Woodstone (talk) 07:26, 7 August 2010 (UTC)

Don't you mean Buys Ballot's law? But this "parachutist" carries a litle thruster, keeping him above the target. So it is not wrong, but Dicklyon has a point, that this example can be confusing. /Pieter Kuiper (talk) 09:24, 7 August 2010 (UTC)

The problem's not that it's right or wrong, but that it's OR. One reason for disallowing OR is that if an editor is allowed to write what they want not based on any source it's very difficult to tell if it's correct, and editors can be tied up forever debating the correctness of an article, or even a section or paragraph. The rules on OR are in place to prevent that – you should always be able to point to a source for every argument and example.

What is clear on top of it being OR it fails [[WP:NOTTEXTBOOK], which says "It is not appropriate to create or edit articles that read as textbooks, with leading questions and systematic problem solutions as examples". The article already has a number of (sourced) examples, with a couple overlong already. It does not need another (unsourced) one.--JohnBlackburne^words_deeds 10:42, 7 August 2010 (UTC)

Woodstone: Thanks for your observations. Apparently the example is not sufficiently clear. The "Earth" is idealized, as is the parachutist falling at a uniform speed, and as the figure indicates is modeled as a rotating flat disk, not as a sphere. The problem is in cylindrical geometry. Its the same model used in the dropping ball example as well. So your objections are for the wrong situation. Brews ohare (talk) 12:49, 7 August 2010 (UTC)

I have added a disclaimer that the "Earth" is a flat disk, not a sphere. Brews ohare (talk) 13:10, 7 August 2010 (UTC)

Blackburne: Your objections are fully discussed above in response to FyzixFighter. You have replied to none of the points, and appear to be engaged in rhetoric, not useful discussion. Brews ohare (talk) 12:53, 7 August 2010 (UTC)

Dicklyon: Your comments are a bit confusing: the section is "bloated" yet it is "packed with information". It is "made up" and "unclear". It would be helpful, if instead of making gratuitous abrasive remarks about my being "kicked off" and "attacking other topics" that are violations of WP:Civil, you were to attempt to point out changes to make things shorter and clearer. Brews ohare (talk) 12:59, 7 August 2010 (UTC)

Pieter Kuiper: I appreciate your comments on the section. I see that the mention of "Earth" as a picturesque term for the rotating flat disk has derailed Woodstone, despite the figure showing a flat rotating disk. Of course, we all like to complicate our lives. Do you have any suggestions for improving the example? I like this example because it complements the preceding one that is very similar. The contrast is more illustrative than a totally new example. However, in view of the barrage of non-specific and nonconstructive complaints above, that make no effort to improve matters, maybe a different example would be better? Brews ohare (talk) 13:33, 7 August 2010 (UTC)

Maybe instead of a parachutist falling to "Earth", it should be phrased as a bird dropping onto a carousel? The dropping ball problem becomes the "dropping droppings" from the bird before it starts flight, and the second one is the descending bird problem. : ) Brews ohare (talk) 13:43, 7 August 2010 (UTC)

You see what happens (again), brews? Non of this would be necessary if you had sources for your lecture. The only thing that can improve matters, is sources, sources and sources. This is a request for comments on whether your lecture is OR or not. Consensus says that it is OR. It stops being OR when it is sourced. So please source it and stop disrupting this talk page? DVdm (talk) 13:48, 7 August 2010 (UTC)

DVdm: So now an RfC is a disruption of a Talk page? I thought it was about improving a proposed contribution. My requests for specifics about what is OR exactly, and what is unclear exactly, and what needs further sourcing exactly, are stonewalled by editors who dismiss this effort with no specific justification, but instead provide vague, nonconstructive assertions, apparently unmotivated by any interest in improving the exposition. Brews ohare (talk) 14:05, 7 August 2010 (UTC)

I have rewritten the example to refer to a bird and a carousel to avoid misinterpretation of the cylindrical geometry shown in the figure. Brews ohare (talk) 13:59, 7 August 2010 (UTC)

And your source for that is? Again, the point of WP is not for editors to write whatever they want but to write an encyclopaedia based on sources. You've been asked repeatedly for sources for what you've written, but you've yet to produce any. Repeatedly ignoring these requests, instead posting an RfC, for the second time in a few days, is certainly not a productive use of your time or anyone else's.--JohnBlackburne^words_deeds 14:19, 7 August 2010 (UTC)

This is not how WP:OR is used in practice on many math and physics articles. While WP:OR explicitely says that simple unsourced deductions are allowed (if the editors agree that it is valid), it does not say that more complex unsourced deductions can never be ok. Like I said before, I've added a quite a few far more complex unsourced derivations (for good reasons) to some Wiki articles without anyone giving a peep. WP:OR is in practice only invoked on such pages if there are real questions about the correctness of the proposed edits and a verification from sources is really needed. Count Iblis (talk) 14:46, 7 August 2010 (UTC)

Blackburne: OK, let's look at this in detail to assist you in becoming specific. Let's ask: What needs to be sourced?

• The first four paragraphs are simply describing the situation to be examined, setting up the discussion. As simply a set-up describing what is to be discussed, that hardly needs to be sourced.
• The statement about no vertical force can be sourced to Newton's law F=ma if you really need that.
• The next paragraph describes the horizontal motion in the rotating frame. There isn't any. I don't think we need a source here, that is simply the description of the vertical path.
• The assertion is made that there is a centrifugal force present in the rotating frame. That can be sourced if you insist, but of course that is the entire subject of this article and so hardly requires a new source. Rotating frames always have centrifugal force.
• The second from last paragraph describes the projection of a spiral path on the horizontal plane as a circular arc. I believe that to be an obvious point: do you want a source describing projection of a spiral down a cylinder as a circle in plane perpendicular to the cylinder?
• The next statement is that circular motion implies a centripetal force. Again, this connection is clear; a link to Centripetal force can be provided if you wish.
• The last paragraph is a summary.

Please go down this list and suggest where you have dissatisfaction. So far as I can see, there is nothing here of such import as to require an OR label or extensive sourcing. I find myself perplexed trying to understand specifically what you object to. Please try to clarify. Brews ohare (talk) 14:49, 7 August 2010 (UTC)

BTW, this RfC was introduced at the request of DVdm, who felt some additional input would be helpful. Please avoid maneuvering to create the appearance of disruption. Brews ohare (talk) 15:13, 7 August 2010 (UTC)

"By DVdm who felt some additional input would be helpful"? No, by DVdm who thought that other users might be able to help you understand the basics of WP:OR again. DVdm (talk) 21:36, 7 August 2010 (UTC)

Another way to deal with this

I've said that I support the inclusion of the text as it stands. However, if I had aded the text myself, I would read the comments as follows. OR is invoked simply because some editors don't like the text, not that there are any real concerns about OR. Then I would guess that the NOTTEXTBOOK objection is a better indication what they don't like about this and rewrite the text to take this into account. What you can do is to make the text shorter, do less detailed (mathematical) explaining. This then leads to the main point that the centripetal force is due to the centrigugal force plus the coriolis force becoming more visible, which isn't that bad. In fact. it could become quite similar to the paragraph I wrote some years ago in the fictitious force page:

In the case of distant objects and a rotating reference frame, what must be taken into account is the resultant force of centrifugal and Coriolis force. Consider a distant star observed from a rotating spacecraft. In the reference frame co-rotating with the spacecraft, the distant star appears to move along a circular trajectory around the spacecraft. The apparent motion of the star is an apparent centripetal acceleration. Just like in the example above of the car in circular motion, the centrifugal force has the same magnitude as the fictitious centripetal force, but is directed in the opposite, centrifugal direction. In this case the Coriolis force is twice the magnitude of the centrifugal force, and it points in centripetal direction. The vector sum of the centrifugal force and the Coriolis force is the total fictitious force, which in this case points in centripetal direction.

No sources were demanded for this at the time, so you should be in the clear if you write about the parachute jump in this way. Count Iblis (talk) 15:23, 7 August 2010 (UTC)

Note that if you take the faux objection of OR too serious, you would have to modify the text in a way that would make it to be disliked even more on the grounds on which it is really disliked. Count Iblis (talk) 15:27, 7 August 2010 (UTC)

Count: Your analysis is quite correct: there is no OR here, and DVdm , Blackburne, and DickLyon habitually use WP:OR or WP:RS as an excuse to malign contributions that they don't want to see included in an article, regardless of pertinence, and without regard for improving contributions or helping contributors. Their reasons for objection, inasmuch as the espoused guidelines are inapplicable, remain obscure. Brews ohare (talk) 15:35, 7 August 2010 (UTC)

I don't routinely use OR and RS where they don't apply. To me, the real issue, as I've stated, is bloat. It might be good to add a guideline some place to say that it's not cool for an editor to just add whatever long-winded examples and tangents that come to mind, to bloat an encyclopedic article into something so long and convoluted that nobody is likely to bother reading it. It baffles me that this kind of contribution, that Brews specializes in, can be seen by anyone as an improvement to the article. Particularly when it is being opposed by many good serious-minded editors, why does Brews continue to push so hard to get his creations included? It's very hard to fathom. And why does Count Iblis habitually back him up in this? Again, somewhat mysterious. Dicklyon (talk) 17:32, 7 August 2010 (UTC)

I'm not "backing Brews up", just explaining to him how to make better progress. You mention that the main issue is "bloat" and that is something concrete that Brews should be able to address. If Brews were to try to address an alleged OR issue that isn't really there, that would result in even more bloat and even more useless talk page discussions, and hence more irritation. So, it is perhaps better not to raise OR or RS as a veto and simply give an honest opinion, even is that's simply "I don't like it". Count Iblis (talk) 17:51, 7 August 2010 (UTC)

Why not raise OR and RS? They are core Wikipedia policies, which every editor should be familiar with. For example at WP:OR#Reliable sources is says "The only way you can show that your edit is not original research is to cite a reliable published source that contains the same material." So which source is this lengthy example from? And your assertion that "OR is invoked simply because some editors don't like the text", do you have any evidence of that?--JohnBlackburne^words_deeds 18:15, 7 August 2010 (UTC)

Upholding OR in this very strict way is not practical for math and physics articles that contain explanations at some detail. This problem has actually be discussed at length on the policy pages and the consensus was always that while the official rules won't be changed it is ok. for the math and physics editors to have a more liberal attitude. I.e. while OR is strictly forbidden, whether or not something is OR is left to the editors to decide; literal quotes from textbooks are not always necessary.

One obvious problem with very strictly sticking to the OR policy to the point of requiring that examples be literally quoted from textbooks, would be that it would be plagiarism to do so. Another issue is that an appropriate example or explanation for a Wikipedia article may not be found in textbooks, as the audience is different. The students who read university level textbooks are assumed to have a certan background knowledge on which the author builds, while Wikipedia is meant to be read by a wider audience with less knowledge. This is something I've frequently encountered when rewriting the thermodynamics articles. But that happened without editing disputes.

We have to keep in mind that the policy pages are edited mainly by people who are active on politics pages. There you'll find the most intractible editing disputes. The text of e.g. OR reflects what's best to manage pages like the one on e.g. Obama in order to prevent too much discussions/ editing disputes about whether his birt certificate is a forgery or not. In this light, it is quite understandable that the general rule is not to allow much more than computing age from birth date. Count Iblis (talk) 19:09, 7 August 2010 (UTC)

Count Iblis: Your remarks make sense, supposing that OR and RS are applied in earnest with a detailed description of the reasons behind their use to assist the contributor to build a better contribution. That hasn't happened here. In fact, my sentence-by-sentence outline requesting whether the designated OR policy applies to this sentence or to that, has been ignored by Blackburne. DickLyon has now no OR objection and has resorted to his customary "bloat" argument, which is, of course, at least partly subjective, and still without specifics. Brews ohare (talk) 19:25, 7 August 2010 (UTC)

(edit conflict)WP:OR is still policy - unless you can point to a page that says otherwise. There's no exception for any sort of article, especially not science where fringe theories and pseudoscience can easily masquerade as science, even with sources (though not reliable scientific ones). And I don't see the problem you mention in your second paragraph. Articles should be sourced, but that does not mean copied verbatim - unless the purpose is to quote. But this should not be a problem as an editor should only be writing about something they understand, so should never need to resort to copying. They should just write what's in the sources in their own words.--JohnBlackburne^words_deeds 19:36, 7 August 2010 (UTC)

John, nobody says OR is not a policy. What has been requested in this instance is evidence that it applies, rather than your own decision that it does apply, which frankly I disagree with. Moreover, if a policy is applied by you, given that I am as aware of this policy as are you, it follows that you and I are not on the same page. We don't interpret applicability to the present material the same way. And so, it behooves you to clarify why you have reached your conclusion. Believe it or not, people can disagree about applicability. The way to reach agreement is to explain yourself so that modification to meet the objection can be attempted. Saying a source is needed is insufficient: what is needed is what the source is supposed to establish, and perhaps why the statement is not obvious on its merits. Going a step further, you might explain what changes would assist your acceptance, in the spirit of crafting a better contribution. Brews ohare (talk) 20:07, 7 August 2010 (UTC)

No evidence that WP:OR applies is needed. Sources for your little textbook essay are needed. The way to reach agreement is that you provide sources, in the spirit of Wikipedia's policies. DVdm (talk)

High time to start writing WP:Ridiculous, I guess. Count Iblis (talk) 22:01, 7 August 2010 (UTC)

DVdm: You have misunderstood: No evidence is needed that WP:OR might apply; what is needed is the basis for saying that it does apply in this case. Sources can be provided if it is clear what exactly the sources are to be selected to establish. Brews ohare (talk) 04:50, 8 August 2010 (UTC)

You might indeed follow Count Iblis' excellent advice. The basis for saying that it does apply in this case is that you try insert a text without sources. It is not up to us to tell you "what exactly the sources are to be selected". It is up to you to provide sources: WP:PROVEIT. DVdm (talk) 10:35, 8 August 2010 (UTC)

Application of WP:OR

Having read what DVdm, DickLyon and Blackburne have to say about WP:OR, I suggest that in their view the following sections of Centrifugal force (rotating reference frame) all are OR:

• 1
• 2
• 3
• 4
• 5
• 6

If I misconstrue how WP:OR is to be applied, according to these gentlemen, perhaps they can point out why these sections are acceptable, in their opinion? That would aid all editors in achieving a uniform application of WP:OR.

I encourage some Talk page discussion before these sections are deleted according to WP:OR, as not everyone may agree. Brews ohare (talk) 00:42, 8 August 2010 (UTC)

I encourage Brews to very carefully read WP:POINT. DVdm (talk) 09:46, 8 August 2010 (UTC)

Why? These are reasonable questions. /Pieter Kuiper (talk) 09:50, 8 August 2010 (UTC)

Perhaps, but do have a look at this guideline. Brews's "invitation" looks like the perfect schoolbook example of WP:POINT: like "if they don't convince me that all these sections are OR, then they haven't convinced me that my section was OR to begin with, so I am free to include it; otherwise I will delete their sections." DVdm (talk) 10:24, 8 August 2010 (UTC)

Trying to apply rules with some consistency seems to be a good idea to me. /Pieter Kuiper (talk) 10:32, 8 August 2010 (UTC)

Sure, go ahead, try to apply rules with consistency. But, looking at the way he formulated the invitation and at his history, I think that, in order to avoid some kind of permanent ban, Brews should stay away from this kind of activity as far as he possible can, if not farther. DVdm (talk) 10:46, 8 August 2010 (UTC)

Pieter and DVdm: A pattern of behavior is emerging here. Rather than respond to requests for clarity or some detail about what is wanted, all such efforts are stonewalled with an It's obvious. Read the guidelines response. Obviously it's not obvious, look at the difficulties. When requests for particulars of these objections are made, in the hope of reaching some accord, the same stonewall non-response is made, and supplemented with advice to try no longer to obtain details of objection, apparently on the basis that it is bothersome for these editors to engage usefully. Brews ohare (talk) 15:03, 8 August 2010 (UTC)