# User talk:Prof McCarthy

## Welcome

Welcome!

Hello, Prof McCarthy, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

I hope you enjoy editing here and being a Wikipedian! Please sign your messages on discussion pages using four tildes (~~~~); this will automatically insert your username and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or ask your question on this page and then place {{help me}} before the question. Again, welcome! John of Reading (talk) 07:08, 28 May 2011 (UTC)

You currently appear to be engaged in an edit war according to the reverts you have made on Machine. Users are expected to collaborate with others, to avoid editing disruptively, and to try to reach a consensus rather than repeatedly undoing other users' edits once it is known that there is a disagreement.

In particular, the Wikipedia's policy on edit warring states that:

1. Edit warring is disruptive regardless of how many reverts you have made; that is to say, editors are not automatically "entitled" to three reverts.
2. Do not edit war even if you believe you are right.

If you find yourself in an editing dispute, use the article's talk page to discuss controversial changes; work towards a version that represents consensus among editors. You can post a request for help at an appropriate noticeboard or seek dispute resolution. In some cases it may be appropriate to request temporary page protection. If you continue to edit war, you may be blocked from editing without further notice.— Preceding unsigned comment added by Derek farn (talkcontribs) 13:45, 29 May 2011

(I'm still rather new to Wikipedia, sorry in advance!) The animated gif works if you click on the picture. It brings you to the file page. I don't know how to animate it in the frame on the linkages page — Preceding unsigned comment added by Alberthyang (talkcontribs) 22:02, 27 June 2011 (UTC)

## Machine

I am responding to the question you left here, per request of DragonflySixtyseven. You need to discuss major changes like these on the talk page of the article, like Derek farn suggested. I see you have posted there, which is good, but you should stop editing the page and wait for him to respond before you continue to rework the lead. It's important that the involved editors come to an agreement and stop reverting each other. What the two of you have been doing is considered edit warring, and is very disruptive. I'd also like to point out that if you are editing as User:68.101.120.164, you should stop doing so. If that's someone else, disregard this, but it seems unlikely that the two of you would work together so fluidly in such a short span of time. 00:54, 30 May 2011 (UTC)

Please understand that I only made a brief change to the formatting of the article on machines and that I am honestly not interested in it at this point. I regret that I will be unable to provide any useful input regarding the content dispute. DS (talk) 03:15, 31 May 2011 (UTC)
In addition, posts like these are not acceptable. Comments on the talk page need to be about content, not about contributors. Please take a gander at this essay and do not ascribe motives to other editors. Also keep in mind that material needs to be able to be sourced to reliable sources and that when material is challenged, as when it is deleted, those sources should be provide explicitly. That "machine" refers only to mechanical systems that do work is one of those things that needs to be sourced. Regards, Danger (talk) 19:38, 31 May 2011 (UTC)
I have not ascribed motives to individuals simply commented on their actions. I cannot understand his motives, because he does not explain them. I do not know how to discuss the content he provides because it does not make sense. When I provide references to document my content, he deletes them. Prof McCarthy (talk) 20:43, 31 May 2011 (UTC)
Copied from User talk:Danger for archival purposes. Ah, I didn't see that you had done that. Thank you very much. At the very least having those recorded in the page history may be useful in the future. I'm very sorry that this experience is frustrating. C'est la Wikipedia, non? What I suggest is waiting a few days for any enmity toward Derek to cool and then asking if he would be willing to seek a third opinion. (If you need help creating the listing, let me know.) I also suggest listing the sources that you are using on the talk page, so that outside editors can see them right away without having to look through the page history. Of course, if you are absolutely finished with Wikipedia, then I'm sorry to see you go and I thank you for the contributions that you've made. Regards, Danger (talk) 20:58, 31 May 2011 (UTC)

Hello. In case you didn't know, when you add content to talk pages and Wikipedia pages that have open discussion, you should sign your posts by typing four tildes ( ~~~~ ) at the end of your comment. You could also click on the signature button located above the edit window. This will automatically insert a signature with your username or IP address and the time you posted the comment. This information is useful because other editors will be able to tell who said what, and when. Thank you. --SineBot (talk) 20:38, 31 May 2011 (UTC)

## Machine article

I'd long given up on trying to bring the Machine article into conformance with the generally accepted nomenclature of science and engineering, Derek Farn having been such a persistent and obstinate obstruction to improving the article. He'd made many absurd edits and was clearly not qualified to judge the accuracy of the article, yet clung to his edits as if he were the resident "expert" on the topic, even though when I entered the fray the only reference was Machinery's Handbook (now relegated to the "See also" section) and there were no in-line citations.

Having given up on trying to reason with Farn (see our extensive discourse, and note my frustration, on the Talk page), I had planned to write a new article, "Machine (mechanics)" or some such thing, but eventually quit wasting my time on Wiki -- too much intransigence from certain editors who seemed to have an agenda other than improving an article. Since Farn is still at it, I recommend you post a note to an administrator (I'll back you re the aforementioned's obstinacy and obvious lack of qualification). I was going to recommend admin VirtualSteve; he was the best, but his talk page now reads "retired". Perhaps he'd just had enough. Anyway, best of luck! Cheers, Rico402 (talk) 12:07, 1 June 2011 (UTC)

Rico402, Thank you very much for getting back to me. I read the exchange between you and Derek farn and tried to take a different tack but no such luck. So at the moment I am simply documenting his intransigence in the discussion page. I have to say that others seem to share your frustration with the Wikipedia experience. It is too bad, because I see Wikipedia growing in influence among my students, which is why I felt compelled to try to make these changes.

## Outline of machines

Dear Prof,

You don't need my permission to work on outlines. Go for it. We need all the help we can get!

There are some pointers at Wikipedia:Outlines, and the project page is Wikipedia:WikiProject Outlines.

Good luck, and have fun. The Transhumanist 00:30, 3 June 2011 (UTC)

P.S.: "Outline" as it is used in the outline project is short for "hierarchical outline", a type of tree structure.

Thank you very much for your encouragement and for you edits to the article on machines. I am trying to work with our colleague Derek farn, but it is difficult. If he insists that the article on machines apply to stand-alone computers, I will not be able to proceed. Wikipedia has an excellent article on computers, and very poor information on machines. We cannot proceed if he continues. Prof McCarthy (talk) 05:17, 6 June 2011 (UTC)

## Separate Mechanical Systems from Machines

 This help request has been answered. If you need more help, you can ask another question on your talk page, contact the responding user(s) directly on their user talk page, or consider visiting the Teahouse.

Colleagues, it seems that only resolution of the conflict regarding the article on machines is to disconnect the link from Mechanical Systems to Machines. Our colleagues Derek farn and Wizard191 insist that the article on machines include computers, televisions, and biological organisms. They delete any discussion of aspects of a machine that they deem is too specialized for their view of machines. Please separate this link and tell me how to create a new article on "mechanical systems" that I and many colleagues in machine theory and robotics can develop to an appropriate level of sophistication. Thank you, Prof McCarthy (talk) 23:32, 7 June 2011 (UTC)

You can just go ahead and create the article at mechanical systems; you do not need administrator permission to do so. However, if you are having trouble reaching consensus on another article, you could try dispute resolution. Reaper Eternal (talk) 01:05, 8 June 2011 (UTC)

## mechanical systems -> machine

the link was not created by an administrator and i dont think that these two are even related.

I am no administrator, but i can help removing the link and then you can start with the page called "mechanical systems" if that is ok with the Administators

Gavin.perch (talk) 23:56, 7 June 2011 (UTC)

Gavin, Thank you very much. I am new to Wikipedia and am finding my way around. I found how to create the new article. Thanks, Prof McCarthy (talk) 00:00, 8 June 2011 (UTC)
Prof McCarthy, I have removed the redirect on mechanical system and cut-and-pasted some words taken from an edit of yours. Hope this helps and that you continue to contribute to Wikipedia. Derek farn (talk) 01:07, 8 June 2011 (UTC)

## Article: Mechanical Systems

Hi Prof

The Article for Mechanical Systems has been approved by an Administrator.

The Link to the machine can now be removed.

Would you like me to remove the link so that you can start the Article?

Gavin.perch (talk) 01:34, 8 June 2011 (UTC)

## Now Derek farn is attacking mechanical system

{{adminhelp}} Colleagues, Derek farn would not allow edits to the article machine that he considered to be too mechanical. This made it impossible to develop the page to its full potential. Please see the discussion section. To accommodate him, I moved to the new article mechanical system. Now, he is cutting out large sections that were written by me, saying that it is duplicative. I need these items to build the article on mechanical systems. This is a work in progress. I have assembled a collection of colleagues who would like to improve the quality of Wikipedia articles on mechanical systems. However, we cannot proceed in the face of this kind of activity. Please stop him from this abuse. Prof McCarthy (talk) 20:04, 8 June 2011 (UTC)

I suggest using WP:AN/I; this looks to be ripe for that noticeboard. —Jeremy v^_^v Components:V S M 20:18, 8 June 2011 (UTC)

## Here is the edit by Derek farn that is abusive

{{adminhelp}} Here is the edit that Derek farn decided to apply to the article mechanical system. [1] You can see the challenges to my edits on the discussion section of the article on machines starting at the entry [2] Please stop him!

I don't see any administrative intervention that is required here. I suggest looking at WP:Dispute resolution. You and your "colleagues" do not own the article, and the fact that another editor has different ideas than you about how the article should be developed is not a reason to take action against that other editor so that you can impose your version. An editor above suggests a report at Wikipedia:Administrators' noticeboard/Incidents, but I don't see that as appropriate. If you did take the dispute there then what the outcome of that would be would remain to be seen: it is certainly not safe to take it for granted that it would be to "stop" the person you disagree with. JamesBWatson (talk) 20:54, 8 June 2011 (UTC)

Thank you for your comments. I am not sure that you see that the dispute over the definition of the mechanical aspects of a machine was carried out in the article machine, and that I agreed to move away from machine to work on mechanical system. And I have been migrating the edits that I created in the article on machine to this article. However, now our colleague Derek farn has elected to eliminate form this new article the very elements that he objected to originally in the machine article. It seems crazy to me, but maybe this is typical Wikipedia behavior. Prof McCarthy (talk) 22:50, 8 June 2011 (UTC)

I confess I have not looked into the history of this thoroughly. I really just looked enough to see that it didn't look like an admin job. However, if you like I will look at it more closely and see if I think there is anything I can do to help as an independent third opinion. I would come in as a completely impartial outsider, as at present I have no opinion as to which side in the dispute (if either) is "right". If you want me to, let me know on my talk page, but I'm afraid I won't have much time to do it over the next few days, so you might prefer to look for someone else if you don't want to wait. I don't know if WP:Dispute resolution has any suggestions that might be useful, but you should certainly look at it if you haven't already. JamesBWatson (talk) 22:59, 8 June 2011 (UTC)

For now I will just keep trying to do a good job on this article. He will make some inappropriate change later today or early tomorrow. I will contact you again at that time, and maybe you can tell me who to talk to. Thank you, Prof McCarthy (talk) 23:04, 8 June 2011 (UTC)

{{adminhelp}} Derek farn removed the reference to Franz Releaux (the founder of modern machine theory) when I added it to the article on machines, the resulting conflict force me to move to form a page on mechanical systems, and now he removed the reference when I added it to the section on mechanical systems. This has reached the point of vandalism. Prof McCarthy (talk) 17:41, 11 June 2011 (UTC)

First off, you should link to the diffs when you mention specific edits, especially when those edits may be vandalism. Second off, while you and Derek have gone back on forth on the Mechanical system article, as far as I can see, it looks to be a content dispute, not vandalism. I second JamesBWatson's idea on looking into dispute resolution. Avicennasis @ 07:03, 10 Sivan 5771 / 12 June 2011 (UTC)

Thank you for your note. When our colleague Derek fran does it again, I will link directly to his changes. I understand that vandalism is a strong accusation, and I will be more clear in my explanation next time. It is difficult to view this a content dispute, when he demands that machines not be limited to mechanical devices, and then will not let mechanical devices be called machines. I am reluctant to enter the dispute resolution process without guidance, and I have not yet found anyone willing to look at this issue in detail. I am sure it is because there are other more exciting topics to work on. All I am trying to do is improve Wikipedia's content on machines. Prof McCarthy (talk) 12:39, 12 June 2011 (UTC)

UPDATE Here is a link to the latest changes by Derek farn deletions. I reverted these changes previously and now he chose to revert them back. One entry is a set of references that characterize machines in terms of power flow. This was a conflict in the article on machines, and to satisfy our colleague I moved to mechanical systems. Now he will not let these references be provided in the article on mechanical systems for some reason. Prof McCarthy (talk) 13:04, 12 June 2011 (UTC)

Please use dispute resolution as advised above. Admins are not moderators and {{adminhelp}} will not be a solution to any editing disputes. Regards SoWhy 08:46, 13 June 2011 (UTC)

## Articles in progress

This is a list of articles that I am working to improve:

I am thinking about working on these:

Additional articles that need work are

• Spherical linkage: this also would be a new article
• Slider-crank: surprisingly, there is no article on this linkage. There is the article Crank (mechanism), but it focusses on the crank.
• Curvature theory: There does not seem to be an article on the instantaneous version of Burmester's theory, which is an interesting area that includes the Euler-savary equation, Ball's point, the cubic of stationary curvature, and the Burmester curve.
• Bennett linkage: this would be a new article
• Linkage type: there are interesting results counting the number of one degree-of-freedom 12, 14, and 16 bar linkages.
• Linkage graph: this would be a new article, perhaps combined with linkage type.

I am not sure what to do with the topics

Also it seems Kinematic pair shows up in several different places. It would be nice to have a good explanation of this fundamental topic.Prof McCarthy (talk) 07:21, 20 June 2011 (UTC)

## Personal sandbox

Hello Prof McCarthy. I have been perusing your User talk page and I notice you have experienced some difficulty with other Users when you have been developing extensive improvements to an article. This is a common problem. Fortunately there is a simple solution that works for many of us.

Please have a look at my personal sandbox where I will be working on improvements to one article or another, or developing a new article. See User:Dolphin51/Sandbox.

I'm pleased to see you have created a personal page to work on Mechanical advantage. I have taken the liberty of editing your page to de-activate the categories and foreign language versions at the bottom of the page. Otherwise, your personal page is added to these categories and shows up on various foreign language version of Wikipedia. I did this by adding nowiki at the beginning of these categories and foreign language tabs, and adding /nowiki at the end. See my diff. When you eventually copy and paste your version into the official article you can re-activate these things by erasing the nowikis. Dolphin (t) 05:53, 5 July 2011 (UTC)

Thank you for your help with this. I will have the revised version of the page ready in a day or so. Prof McCarthy (talk) 06:06, 5 July 2011 (UTC)

I have left you a message at User talk:Prof McCarthy/mechanicaladvantage and made some suggested changes to your draft article. Dolphin (t) 03:57, 7 July 2011 (UTC)

## A common problem

Dear Wikipedist editor, I want to submit to your attention an our common problem: disruptive contributions and edit warring operated by user Derek farn (talk). This latter shows systematically a provoking behaviour and lacking of respect for other people’s work, typical of vandalism. I’ve sent this communication to many people having the same problem in order to organize a collective protest/action request directed to e.g. the Arbitration Committee or Requests for comment/User conduct (this latter procedure requires the participation of at least two users) or to the Wikipedia Community. If you agree with this initiative please contact me at this dedicated email address: clipeaster-1971 AT yahoo DOT com. In order to avoid creating of a forum section dedicated to Derek farn I suggest you to delete this communication once you’ve read it and, then, be in contact via email. Any suggestion are welcomed. I look forward to hearing from you. Best regards, Structuralgeol (talk) 17:15, 15 July 2011 (UTC).

As another user pointed out to me that suggesting to be in contact outside wikipedia is not a correct way, for transparency reasons, so I conclude that we need to correspond via talk page. Best regards, Structuralgeol (talk) 02:27, 16 July 2011 (UTC).

Hi,

I wrote a brief paragraph on the Mechanical Advantage article, perhaps to illustrate the exact cases, a horizontal plane should be considered etc. Would appreciate your comments — Preceding unsigned comment added by Alokdube (talkcontribs) 10:30, 17 August 2011 (UTC)

I would be pleased to look at it.Prof McCarthy (talk) 11:11, 17 August 2011 (UTC)

Hello, Prof McCarthy. You have new messages at Vrenator's talk page.
You can remove this notice at any time by removing the {{Talkback}} or {{Tb}} template.

## Categories

I noticed that recently you have been adding various categories to articles as well as other categories, all related to mechanical engineering subjects. Where there was a rather clear hierarchical structure in the categories you have now introduced something that I am not even going to try to understand. Maybe there is some logic to it that I don't understand, however, in other subjects this cross-categorization is, as far as I know, not allowed. It may happen that somebody else, better versed in this subject, may notice it as well, consider it a problem, and reverse these categories. --VanBurenen (talk) 08:16, 14 October 2011 (UTC)

VanBurenen, if my attempt to categorize the articles that refer to machines and mechanisms bothers you, then I will leave it alone. I have found over the last year that Wikipedia is increasingly the first stop for my students interested in machines, and in my opinion the articles have been poorly written and poorly categorized. I do know know why you view my effort to improve the sparse and inconsistent listings of these categories to be chaotic and unmanageable. I believe those interested in machines and mechanisms deserve better, but I am not interested in arguing over it even in a friendly way. I made my changes to the categories because I thought it would help the reader. Prof McCarthy (talk) 16:40, 23 October 2011 (UTC)

Firstly, I do appreciate your input (as much if not more as your students do). Secondly, my use of the term "chaos" refers to the assigning of any possible category to an article: overcategorization. I apparently failed in making my point of view clear or appreciated. May the force be with you in future edits :). --VanBurenen (talk) 17:17, 23 October 2011 (UTC)

## Speedy deletion nomination of Change for Balance Productions

If this is the first article that you have created, you may want to read the guide to writing your first article.

You may want to consider using the Article Wizard to help you create articles.

A tag has been placed on Change for Balance Productions requesting that it be speedily deleted from Wikipedia. This has been done under section A7 of the criteria for speedy deletion, because the article appears to be about an organization or company, but it does not indicate how or why the subject is important or significant: that is, why an article about that subject should be included in an encyclopedia. Under the criteria for speedy deletion, such articles may be deleted at any time. Please see the guidelines for what is generally accepted as notable.

If you think that this notice was placed here in error, contest the deletion by clicking on the button labelled "Click here to contest this speedy deletion". Doing so will take you to the talk page where you will find a pre-formatted place for you to explain why you believe the page should not be deleted. You can also visit the page's talk page directly to give your reasons, but be aware that once tagged for speedy deletion, if the page meets the criterion, it may be deleted without delay. Please do not remove the speedy deletion tag yourself, but don't hesitate to add information to the page that would render it more in conformance with Wikipedia's policies and guidelines. If the page is deleted, you can contact one of these administrators to request that the administrator userfy the page or email a copy to you. mc10 (t/c) 03:19, 31 October 2011 (UTC)

## Johnmichael123456

What (if any) connection do you have with the user who edits under the name Johnmichael123456? JamesBWatson (talk) 11:24, 31 October 2011 (UTC)

This is a team of young men who have been friends of my family for many years. They did the video work for the 2011 UCI Energy Invitational as well as other projects that you can see on my web page mechanical design101. Their documentary on horse slaughter was recently recognized with a top three place in the Classy Awards for non-profits. Johnmichal123456 asked me how to set up a Wikipedia page and I showed him. If their work is not appropriate for Wikipedia, then simply tell them. Prof McCarthy (talk) 15:19, 31 October 2011 (UTC)
Thanks a lot for the clarification. At first I thought that it looked as thought his was another account of yours, but looking more closely that seemed unlikely, so I thought I would ask you what the connection was. JamesBWatson (talk) 15:37, 31 October 2011 (UTC)

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## Assessment of articles

First of all, I would like to invite you to join the Robotics project Wikipedia:WikiProject_Robotics/Participants and let you know about the assessments request page Wikipedia:WikiProject Robotics/Peer review.

Please do not self-assess articles where you have done significant work. This would be like allowing a student to mark their own paper. Can you please tell me all those articles that you have done this on?

I am also becoming aware that some of your edits seem to be turning the articles into equations and theory from previously accepted definitions of practical application. For example, kinematic chain. The first sentence now introduces the topic as *"Kinematic chain refers to the mathematical model of a mechanical system", the previous definition being:

If the definition of kinematics is correct, then a kinematic chain is a chain of those kinematic objects, not merely some mathematical model of them.

• "Kinematics ... describes the motion of points, bodies (objects) and systems of bodies (groups of objects) without consideration of the forces that cause it."

My biggest concern is why you changed the picture description on Forward kinematics from 7 DOF to 6 DOF?

I feel that at this point I am obliged to check all the work you have been doing to ensure that your edits have not caused any issues. While I understand that you are saying you are a professor, you should understand that I am requesting a review of your work to satisfy myself that standards are being upheld. For now, I ask you to not assess anything and place a request on the Robotics assessment request page for anything you consider needs assessing.

Thanks Chaosdruid (talk) 20:00, 15 January 2012 (UTC)

Thank you for the prompt reply. Please do not feel that there is anything untoward being considered, merely a review of the large amount of work you have done here over the last few weeks. I realise that you are a relatively new editor, and hope that you see my comments as trying to help you understand how things are done and to allow a period of "settling in". I also aim to explain why I think certain things are incorrect and to help us achieve consensus; for example, I saw that you had changed the Kinematics importance to high. If it was not clear in my previous message, that was a decision I fully supported.
I hope that you will consider joining the Robotics project, we are in great need of robotics experts who actually wish to work on articles :¬)
I understand that you are in the field, could you please explain exactly what part of the field you work in? THis would help us identify your expertise and also to avoid any COI issues. Chaosdruid (talk) 21:01, 15 January 2012 (UTC)
I am glad we have resolved the kinematic chain solution. I am still perturbed at the 7 DOf -> 6 DOF issue though, can you tell me why you did that? Chaosdruid (talk) 02:29, 17 January 2012 (UTC)

Just to let you know, if you want to link to an article talk page, you can do it in two ways:

• Direct link to the talk page in general - simply insert "Talk:" before the article title:
• Directly link to a section on the talk page - best way is to click on the link from the contents table at the top of the page, then copy and paste the part starting with "Talk:" from the location bar in your browser:
• To make things easier we can use a separator to put descriptive wording in the link (though the blue text colour can easily be missed in blocks of text:
• [[Talk:Robotics#Robotics_is_a_scientific_field.2C_To_much_speculation_and_science_fiction_in_the_article|which is here]] gives section is here

Also we have a system of indentation, each new post being indented one more than the previous post. It makes things much easier to follow in discussions. When it reaches level 6, 7, or 8, you can use {{od}} to produce: ────────────────────────────────────────────────────────────────────────────────────────────────────

Hope that helps :¬) Chaosdruid (talk) 19:35, 17 January 2012 (UTC)

Thank you. Prof McCarthy (talk) 19:45, 17 January 2012 (UTC)

## EDits and discussion

Hi

I notice that you have decided that the discussion is completed and have edited the other articles to match. Consensus is not yet formed. Please read WP:BRD and WP:CONSENSUS, also please be aware that the burden of proof is on the person proposing the change to provide evidence that supports the change; and thus to find consensus to support the change(s).

I am not convinced yet that you are correct. I realise this may cause you consternation, but here we do not expect things to be decided on without consensus, or at least more than two people discussing something - it is true that I have had consensus discussions go on for months at times, often because there is not enough throughput to the article talk page or interest in a particular subject.

I am a little disturbed that you chose to make that comment on the kinematics talk page, where I have left a reply. Chaosdruid (talk) 22:07, 20 January 2012 (UTC)

## Yes we do...

The section is called "Historical Uses of the Simple Machine". These are just some historical uses of the simple machine. And it really isn't an exposition as you descibe it.Algamicagrat (talk) 14:58, 17 February 2012 (UTC)

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## Some content at kinematics

Hi, I was just noticing your contributions to articles on kinematics. In particular, there are some unexplained references to the "Watt topology". When searching the web under this term, there did not seem to be any other sources on the topic. The only mention seems to be in your own publication, which I notice appearing as a reference in a few articles you edit heavily. I just wanted to alert you that there are policies against such self-reference, and I wanted to encourage you to find more secondary sources supporting the topic (maybe there are other terms which I didn't think of for "watt topology"). If such citations are not provided, the content might be challenged/removed. Happy editing: Rschwieb (talk) 15:04, 21 March 2012 (UTC)

The fact that six-bar linkages have two topologies one named after Watt and the second after Stephenson has been known for over a hundred years. It may be that the side-by-side placement of the words Watt and topology may not be regularly searched terms on google but that does not change the well known fact that "Watt six-bar" and "Stephenson six-bar" refer to the two topologies of a six-bar linkage. Prof McCarthy (talk) 15:44, 21 March 2012 (UTC)
Here is information on Watt six-bars from the McGraw-Hill web-site http://www.mhhe.com/engcs/mech/norton/norton/ch2/watt's_sixbar/watt's_sixbar.htm The best book on this topic is by Lung-Wen Tsai: http://www.amazon.com/Mechanism-Design-Enumeration-Structures-Engineering/dp/0849309018 I do not know what it takes to rebut this type of accusation. In the past I have found it generally difficult to convince any editor in any conflict on a topic in machines and mechanisms. I hope this is enough. Prof McCarthy (talk) 16:01, 21 March 2012 (UTC)
Sorry to hear you've been having some troubles with editors. I changed the citation for these topologies so it points to the page on which they are defined. That should be good enough. Adding your other two links would help too. RockMagnetist (talk) 16:17, 21 March 2012 (UTC)
Thank you for the note. I think this is just part of the Wikipedia experience for better or worse. I will add the links that you recommend. Prof McCarthy (talk) 16:49, 21 March 2012 (UTC)
Glad to help. It's surprising how often the real experts get discouraged and leave, and I'd like to prevent that if I can. RockMagnetist (talk) 17:23, 21 March 2012 (UTC)
@RM : I hope you reonsider the label of "trouble" for my action. The policy I mentioned is an important part of WP, and I did my best to give due courtesey to all parties concerned.
@JMM While I appreciate the answer you gave on my talk page, I never questioned the truth of the statements. I was just checking if it was cited according to WP standards. Rschwieb (talk) 18:14, 21 March 2012 (UTC)
Rschwieb, I believe RM was referring to my expression of frustration with previous experiences with editors in a similar situation. I have found other editors interpret WP policies in such Byzantine ways that it becomes impossible to provide correct information in an article. It seems that to some editors it is about opinion and process and little concern is paid to the ultimate correctness of the article. This was not meant to be attributed to you or your concern about improving this article. Prof McCarthy (talk) 19:54, 21 March 2012 (UTC)
Prof McCarthy is right, Rscwieb. I wasn't referring to your actions. RockMagnetist (talk) 21:44, 21 March 2012 (UTC)
Oh ok, my misunderstanding :) Then I look forward to future interaction with both of you and the physics project :) Let me know if I can help with mathematics, somehow.
JMM, I noticed you contribued to the Clifford algebra page previously, and that is a topic I am learning about. Have you ever included Clifford algebra in a course? Rschwieb (talk) 22:58, 21 March 2012 (UTC)
I use the structure of Clifford algebras to motivate the construction of quaternions and dual quaternions much like I wrote in the article on Clifford algebras. With a little effort you can then show that these encode rotations and spatial displacements by directly incorporating their invariants, that is the rotation axis and screw axis. Finally, the Clifford algebra product can be shown to be the formula for computing the composite vertex of spherical and spatial triangles formed formed by the invariants of the two factors. It is a remarkable meeting of algebra and geometry. Prof McCarthy (talk) 05:11, 22 March 2012 (UTC)
It really is... I hope it continues to grow! Rschwieb (talk) 12:58, 22 March 2012 (UTC)

## Don't bite the newcomers

I found the edit summary you used with this revert very disturbing. Please remember that this is the encyclopedia that anyone can edit. As a member, you are obligated to work together with others on a collaborative basis, regardless of whether or not they have an account. Please do not bite the newcomers. Thanks! Evanh2008 (talk|contribs) 07:26, 11 July 2012 (UTC)

## Anonymous editors

In your edit summary here you ask an IP editor to identify him or herself, and appear to give that as a rationale to revert their edit. IP Only editors have as much right to edit Wikipedia as you or I have. Sufficient edit rationale was given in their removal of material which reflects the comments on the article's talk page, though those comments had not reached a conclusion. They were entitled to their edit in any case, but the more so since they may well have made the valid assumption from the talk page that the figure in question was, at best, placed poorly. Other criticisms were also levelled at the figure on the talk page, however. They were thus bold in their edit, and are to be commended.

You may disagree with that edit, as may any editor, but, when disagreeing, challenge the edit, not the editor, please. Fiddle Faddle (talk) 07:31, 11 July 2012 (UTC)

Good reminder. thank you. Prof McCarthy (talk) 11:15, 11 July 2012 (UTC)
I think it might be useful if you were to take part in the talk page conversation there about the bicycle diagram. There is also a discussion starting there about a lever model. My physics is so long ago and has lain unused for so long that I have forgotten more than I learned, so I can see a decent discussion developing, but lack the competence to participate. Fiddle Faddle (talk) 13:12, 11 July 2012 (UTC)
This is thoughtful of you. But our colleague Jimbowley has a very particular view, and I have expended enough effort over his concern that a wheel is not a machine. At the moment, I am satisfied to let him do what he wants with the figures as long as he is careful with the text. Thank you though. Prof McCarthy (talk) 16:18, 11 July 2012 (UTC)
One needs to achieve consensus rather than simply allow one editor's views prevail even if that editor is ourself :). So I still commend the discussion to you. It is selfish of me rather than thoughtful. In all things where there is a difference of opinion on Wikipedia consensus rules the day. This is, of course, somewhat unlike scientific research where current facts and truths win the day. Fiddle Faddle (talk) 20:05, 11 July 2012 (UTC)

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## A barnstar for you!

 The Tireless Contributor Barnstar I award the Tireless Contributor Barnstar to Prof McCarthy for his prodigious efforts to expand and improve Wikipedia's coverage of essential topics in mechanics and mechanical engineering. Dolphin (t) 12:59, 29 August 2012 (UTC)

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## thanks!

Lookang (talk) 08:41, 18 October 2012 (UTC)

## Happy New Year

In NY already! I see you're hooked. Dicklyon (talk) 05:16, 1 January 2013 (UTC)

## Typography

Hello!

I noticed your contributions in the center of mass article. There are some pieces of non-standard typesetting:

• [4] – please, avoid the use of hyphen-minus as a surrogate; see WP:−.
• [5] – please, put index variables such as i, j, k, l, m, n in italic. You may make it with the wiki code ''i'', either standalone or inside {{math}}. BTW, this is the case for almost all variables, not only index ones.

Hyphen-minuses and Roman variables look unprofessional. You may use [itex] if you are not willing to care about the wiki-code typography. Incnis Mrsi (talk) 12:27, 20 January 2013 (UTC)

[6] no. You may not italicize neither numerals nor symbols, like parentheses, equal signs and commas. Also, learn please that the equals sign has usually spaces around it, like other infix operators with low precedence. You may consult WP: WikiProject Mathematics if you have further questions. Incnis Mrsi (talk) 17:00, 20 January 2013 (UTC)

## Your GA nomination of Moment of inertia

Hello, I just wanted to introduce myself and let you know I am glad to be reviewing the article Moment of inertia you nominated for GA-status according to the criteria. This process may take up to 7 days. Feel free to contact me with any questions or comments you might have during this period. Message delivered by GA bot, on behalf of Corvus coronoides -- Corvus coronoides (talk) 20:06, 31 July 2013 (UTC)

## Your GA nomination of Moment of inertia

The article Moment of inertia you nominated as a good article has failed ; see Talk:Moment of inertia for reasons why the nomination failed. If or when these points have been taken care of, you may apply for a new nomination of the article. Corvus coronoides talk 20:51, 31 July 2013 (UTC)

## Power - product of force and velocity

Hi Prof McCarthy! I've noticed your contributions to various articles like Power (physics) and I've requested a clarification concerning an apparent trivial situation on that talk page. I hope you will clarify that situation and thanks (in advance) for your input.--188.26.22.131 (talk) 14:46, 1 August 2013 (UTC)

As Dicklyon notes in answer to your question, the values of velocity and acceleration in your formulas are evaluated at the same instant of time. Prof McCarthy (talk) 15:21, 1 August 2013 (UTC)

## Satellite orbital movement

Concerning some general application of dynamics and kinematic equations to orbital movement of satellites, could you clarify some aspects concerning equations of movement on spirals of satellites in non-steady state orbital situations?--188.26.22.131 (talk) 09:55, 2 August 2013 (UTC)

How frequently occurs this situation? Given, say the equation of the logarithmic spiral r as a function of angle, what is the equation of motion of the satellite?--188.26.22.131 (talk) 10:00, 2 August 2013 (UTC)

The equation of motion is the same. It relates the forces on the satellite to its acceleration. If gravity is the only force on the satellite then it follows a trajectory that is a conic section and not a logarithmic spiral. Prof McCarthy (talk) 15:12, 2 August 2013 (UTC)
What expression of force would be required for a (logarithmic) spiral trajectory of the satellite? I've remember browsing something about spiral trajectory of satellites (in non-stationary orbits) but I don't remember exactly in what source.
Concerning the spiral trajectories, they seem to be connected to a force expression of an inverse cube, as pointed out apparently by Roger Cotes and Newton. Newton seems to have thought of necessity to add an inverse cube term to his gravitational law in the context of analyzing the apsidal motion of Moon.--188.26.22.131 (talk) 12:28, 12 August 2013 (UTC)

## kinematics

How is it called the vector field of speed of a moving system at a given time in kinematics? In Italian wikipedia we have a page (atto di moto). Thank you. 201.79.225.168 (talk) 06:41, 8 February 2014 (UTC)

## Punctuation of equations

Hello Michael. I have perused the changes you made today to Work (physics) and I noticed that where you displayed an equation on its own line you usually added a period or comma to the last term in the equation. For example, you added:

${\displaystyle {\frac {d}{dt}}r^{-1}=-r^{-2}{\dot {r}}=-{\frac {\dot {r}}{r^{2}}}.}$

Another example is:

${\displaystyle U={\frac {GMm}{r}},}$

I am curious about your personal view on the value of adding punctuation at the end of an equation which is placed on its own line. My personal view is that an equation given prominence by being placed on its own line should not be burdened by juxtaposition of unnecessary punctuation.

In Wikipedia’s Manual of Style for chemistry articles, there is a section devoted to line equations. No mention is made of any requirement for punctuation at the end of chemical equations. See Wikipedia:Manual of Style/Chemistry#Line equations. In the article Chemical equation there are many examples of chemical equations but none of them is burdened by a comma or period.

Unfortunately there is no section of Wikipedia:Manual of Style specifically for articles in physics or engineering. In the section of the Manual of Style for mathematics articles, there is a section devoted to punctuation after formulae and it is quite doctrinaire:

Just as in mathematics publications, a sentence which ends with a formula must have a period at the end of the formula. This equally applies to displayed formulae (that is, formulae that take up a line by themselves). Similarly, if the conventional punctuation rules would require a question mark, comma, semicolon, or other punctuation at that place, the formula must have that punctuation at the end. (SeeManual of Style)

I am inclined to leave the Manual of Style for math articles to the mathematicians, but I have a keen interest in how equations are presented in articles on physics, chemistry and engineering. When an equation is placed on its own line it is being given prominence for various purposes. In that situation, punctuation is subordinate to the equation and can be omitted. There should be no ambiguity because commencement of the next sentence will be marked by a leading capital letter and possibly also commencement of a new paragraph.

For the same reason, when a sentence ends with a graph or diagram, I think it is unnecessary to place a period adjacent to the graph or diagram.

I would be pleased if you could give me your personal view on punctuating displayed formulae. Dolphin (t) 05:46, 12 February 2014 (UTC)

My understanding is that displayed equations are nouns that generally fit into sentences as the objects of a phrase, which means the punctuation associated with the phrase carries over to the equation. It is likely that this reflects my experience presenting equations as a sequence of operations intended to derive a conclusion for the classroom and conferences. The fact that I write this way has resulted in some Wikipedia criticism, so I am not ready to advocate this style. Prof McCarthy (talk) 06:22, 12 February 2014 (UTC)
Many thanks for your very prompt reply! I have beside my keyboard at present my copy of Circuits, Devices and Systems, Ralph J. Smith (1966), John Wiley & Sons Inc New York. It contains many equations displayed on their own lines but none ends with a comma or period. (In a few places, two or more equations are presented on the same line and they are separated by commas.) All equations are beautifully presented. Best wishes. Dolphin (t) 06:48, 12 February 2014 (UTC)

## Your edits at Matrix similarity

I have reverted all your edits at Matrix similarity, because of the difficulty keeping only the few ones that deserve to be kept. In fact your edit consists of

• Changing n-by-n into nxn: nxn is incorrect. n×n would be correct, but may be too technical for some readers.
• Changing ${\displaystyle B=P^{-1}AP}$ into ${\displaystyle K=BAB^{-1}}$: Previous notation is standard, and your notation is misleading, suggesting wrongly that K and A play different roles and B and A have a similar role (in your notation, B is invertible and A is not necessarily invertible).
• Adding detailed proofs of some properties of similar matrices before the section "Properties" where all properties of similar matrices are given. Moreover these proofs are over-detailed. In particular, the section on the eigenvalues could be reduced to the remark that the eigenvalues are the roots of the characteristic polynomial.

The property "if A and B are the matrices of a linear map over two different bases, then A and B are similar", deserve to appear in the section "Properties". For the proof, my opinion is that the proof is misplaced here, and must be replaced by a link to Change of basis#The matrix of an endomorphism. D.Lazard (talk) 10:03, 8 February 2015 (UTC)

## Lagrangian mechanics and Generalized coordinates

Hi, since you contributed significantly to the latter article, I would be grateful for feedback on these talk pages here (Lagrangian mechanics) and here (generalized coordinates). Thanks in advance, M∧Ŝc2ħεИτlk 09:14, 26 September 2015 (UTC)

## ArbCom elections are now open!

Hi,
You appear to be eligible to vote in the current Arbitration Committee election. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to enact binding solutions for disputes between editors, primarily related to serious behavioural issues that the community has been unable to resolve. This includes the ability to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate, you are welcome to review the candidates' statements and submit your choices on the voting page. For the Election committee, MediaWiki message delivery (talk) 16:49, 24 November 2015 (UTC)

## ArbCom Elections 2016: Voting now open!

 Hello, Prof McCarthy. Voting in the 2016 Arbitration Committee elections is open from Monday, 00:00, 21 November through Sunday, 23:59, 4 December to all unblocked users who have registered an account before Wednesday, 00:00, 28 October 2016 and have made at least 150 mainspace edits before Sunday, 00:00, 1 November 2016. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to impose binding solutions to disputes between editors, primarily for serious conduct disputes the community has been unable to resolve. This includes the authority to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate in the 2016 election, please review the candidates' statements and submit your choices on the voting page. MediaWiki message delivery (talk) 22:08, 21 November 2016 (UTC)

## Welcome to The Wikipedia Adventure!

Hi Prof McCarthy! We're so happy you wanted to play to learn, as a friendly and fun way to get into our community and mission. I think these links might be helpful to you as you get started.

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