Talk:Fourth, fifth, and sixth derivatives of position

Jerk [a retrofitted talk-section heading]

Could someone place into the article an example of when snap occurs (a change in jerk) in real life, much appreciated! --71.166.133.153 (talk) 20:01, 7 May 2008 (UTC)

A vehicle accelerating under fixed power and subject to air resistance. Acceleration will gradually decrease, so there's negative jerk. But since acceleration never becomes negative, there has to be non-zero snap. And every higher derivative for that matter. M0ffx (talk) 22:28, 25 May 2009 (UTC)

Although your example does indeed give (non-zero) jounce, your last sentence is not correct. Any further derivations of jounce are all zero, because the jounce works out to be a constant. (And I assume that when you say "acceleration never becomes negative", you mean acceleration never becomes negative in this example – of course, acceleration can be negative, in any system where velocity decreases.)

ΣF = ma = F_driving – F_drag = F_driving – ½ ρ A C v²

So, a = [ F_driving – ½ ρ A C v² ] / m

Derive that once to get jerk = – (ρ A C v ) / m

Derive jerk to get jounce = – (ρ A C) / m

Since jounce is a constant with respect to time, any further derivations will be zero.

An example where all further iterations of derivation will actually be non-zero is angular motion. Since it has a sine function in it, you can derive it to the nth derivative with respect to time and still get a non-zero solution. Strikehold (talk) 21:45, 15 July 2009 (UTC)

"...an example of ... a change in jerk in real life ...". Those are usually called elections. —Preceding unsigned comment added by 219.89.234.138 (talk) 12:19, 31 December 2010 (UTC)

Snap! — Preceding unsigned comment added by 71.13.209.6 (talk) 09:05, 13 January 2012 (UTC)

What about the expansion/collision of the universe ? Surely there must be some derivative of position negative. —Preceding unsigned comment added by 193.29.5.6 (talk) 10:24, 12 May 2010 (UTC)

Removal of snap from the lead

The one web page that every article on Wikipedia references says itself the names "snap", "crackle" and "pop" are made up. This is that page http://math.ucr.edu/home/baez/physics/General/jerk.html. I am a physicist and have never seen this term used in any text. For additional info see my talk page. I am removing from the lead. To re-add please first provide a reference to a classic physics text that uses the term. Phancy Physicist (talk) 17:55, 10 March 2012 (UTC)

According to the website quoted in your post "There is no universally accepted name for the fourth derivative, i.e. the rate of change of jerk, The term jounce has been used but it has the drawback of using the same initial letter as jerk so it is not clear which symbol to use. Another less serious suggestion is snap (symbol s), crackle (symbol c) and pop (symbol p) for the 4th, 5th and 6th derivatives respectively. Higher derivatives do not yet have names because they do not come up very often. Since force (F = ma) is rate of change of momentum (p, symbol clashes with pop) it seems necessary to find terms for higher derivatives of force too. So far yank (symbol Y) has been suggested for rate of change of force, tug (symbol T) for rate of change of yank, snatch (symbol S) for rate of change of tug and shake (symbol Sh) for rate of change of snatch. Needless to say, none of these are in any kind of standards, yet. We just made them up on usenet."

In all of my physics classes, I am studying to become an engineer, we have always referred to the derivative of jerk as SNAP. And by your OWN sources admission the names are made up and there are no standards yet. Therefore the title should be something along the lines of "Derivative of Jerk" or "Fourth Derivative of Position" not Jounce which can be misleading. — Preceding unsigned comment added by B787 300 (talk • contribs) 02:35, 12 October 2012 (UTC)

First, I want to make it clear that I was removing snap because there where no sources in the article to support that term, I didn't name the article. If you could supply a source like one of your text books that would be great and we could work on getting the term properly sourced.

Second, I agree that Jounce is bad too because there is no source for that term either. I think your idea to rename the article Fourth Derivative of Position is a good one until proper sources for Snap or Jounce can be added if they exist.

Phancy Physicist (talk) 06:58, 20 November 2012 (UTC)

Why are we still using 'jounce'? And why does the source have to be from 'classical' physics? What is classical physics? These papers use 'snap' and define the word in the text; www.normalesup.org/~pham/docs/locotraj-smoothness-cur.pdf www.seas.upenn.edu/~dmel/mellingerICRA11.pdf Brocerius (talk) 07:38, 18 November 2012 (UTC)

You are right in suggesting that the source doesn't have to be a classical physics text just widely referenced or used scientific text. These are not my rules, they are Wikipedia's. -> Wikipedia:NEO#Neologisms I think this link to Wikipedia policy supports the renaming suggested above by B787 300 until solid sources can be found.

Phancy Physicist (talk) 06:58, 20 November 2012 (UTC)

The Mellinger paper from above (here is an official link: ) has 515 citations on Google scholar, and is published at a well respected, peer reviewed conference. Seems quite solid. Max Pflueger (talk) 15:44, 2 August 2017 (UTC)

I agree. I've never heard of "jounce" all my coursework and professionally I've heard it as snap (along with crackle and pop, of course). It's not a physics textbook, but snap is in wide use. For example, https://github.com/synthetos/TinyG/wiki/Jerk-Controlled-Motion-Explained . I suspect it won't show up in physics but rather in engineering of motion-control systems where the time derivative of jerk can be a limitation of your system (believe it or not!). I suspect that some witty overworked controls grad student got snap, crackle, and pop started at some point and now that there are engineers who actually care about those derivatives, we are using it. One of the references on this page even says "Snap [the fourth time derivative] is also sometimes called jounce."[1] I'm tempted to be bold, take a crack at editing this page by popping snap back in there. —Ben FrantzDale (talk) 02:07, 4 August 2017 (UTC)

I re-added snap to the lead. Googling around, it seems like there is a lot of traction for snap. I also question the claim "However, derivatives of higher order than jounce are not useful and there is no consensus among physicists on names for them." I toned down that language ("not useful" is a strong claim). But as for "no consensus", isn't there consensus for "crackle" and "pop"? I've never heard any competing names, and clearly people who spend their days thinking about motion control are using them. —Ben FrantzDale (talk) 02:17, 4 August 2017 (UTC)

For one example in motion control, consider a quadcopter. Vehicle acceleration goes by rotor velocity. Rotor velocity is forced by current through the coils. Current through the coils is changed by changing voltage. Voltage can be changed at a rate limited by the DAC slew-rate limit. So if voltage slew-rate is piecewise constant (i.e., C^-1 continuous, 0th-order polynomial), voltage is 1st-order, current is 2nd-order, rotor angular velocity and so thrust and so vehicle acceleration is 3rd-order, velocity is 4th-order and so vehicle position is 5th-order, i.e., finite crackle. It's a physical system, but not something that you'd find in a physics text book, but totally relevant to controls, 'cause the realizable trajectories would have to have bounded velocity, acceleration, jerk, snap, and crackle. —Ben FrantzDale (talk) 13:14, 4 August 2017 (UTC)

References

Revert undiscussed rename

[2] from jounce to fourth derivative of position. This is against COMMONNAME, and was also undiscussed (here at least). Jounce is hardly a common term, but it is the common term used for this derivative of acceleration (there's an argument to be made in favour of snap, crackle and pop too). I suppose we should be grateful it's not redirected to jerk any more (which is just plain wrong).

As there seem to be AfDs etc. popping off all over the place, do we need some coherent single discussion to sort out all of these? Andy Dingley (talk) 12:00, 22 March 2020 (UTC)

I agree that it would be helpful to reach a proper consensus on the organization of jerk and its derivatives. Thtatithticth (talk) 12:46, 22 March 2020 (UTC)

Requested move 25 March 2020

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: in-process move to be about all three (Fourth, fifth, and sixth derivatives of position), so requested move no longer really applies. Maybe we should do a requested move for "Snap, crackle, and pop (physics)" (or, if you really want to use the individual WP:COMMONNAMEs, "Jounce, crackle, and pop" – which would be a bit weird, so idk). Paintspot Infez (talk) 02:12, 25 March 2020 (UTC)

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Fourth derivative of position → Jounce – Until recently this was the article's title and somebody moved it for no real reason other than WP:IDONTLIKEIT. Georgia guy (talk) 00:32, 25 March 2020 (UTC) Georgia guy (talk) 00:32, 25 March 2020 (UTC)

• Support Jounce. Andy Dingley (talk) 00:43, 25 March 2020 (UTC)

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The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Too many undiscussed moves

These need to stop. Jounce was changed to a redirect to jerk (physics) after a short discussion, then restored and moved to Fourth derivative of position with no discussion, then a discussion was raised to revert it back to jounce but it was, instead, moved to Fourth, fifth, and sixth derivatives of position, with no discussion leading to the decision as far as I'm aware.

That's not to say I don't agree with this move; I think this is the best option, be it under this name or Snap, crackle and pop (physics). Regardless, the constant moving is both confusing and unnecessary, and should stop unless a there is an actual consensus for a target. Thtatithticth (talk) 06:33, 25 March 2020 (UTC)

Do we really need that image in the intro?

I removed it the other day because it's confusing, garish, and full of terms that are neither used in the literature nor explained in this article. It was apparently reintroduced during a content merge. I still think it's a detriment to the page overall, and I'd like to snip it out again, but I don't want to step on anybody's toes. XOR'easter (talk) 19:15, 25 March 2020 (UTC)

It is absurd, probably only a joke. ⸻Nikolas Ojala (talk) 19:27, 25 March 2020 (UTC)

Not a joke, but not necessary worthy of inclusion either. I have the impression that it relates to work by Steve Mann and some of his colleagues. His work often comes across as less than serious, but there is more to it than it at first appears.--Srleffler (talk) 03:04, 28 March 2020 (UTC)

Well, but I'd like to have an image explaining about 1st~6th derivatives of position because it makes easier for people to understand the context of this page (since this article contains 3 variables). But, it could be more simpler than the removed image... Luke Kern Choi 5 (talk) 02:01, 1 April 2020 (UTC)

XOR'easter, Luke Kern Choi 5: I've thrown together a simpler image here (and here, but I prefer the first one). Do you think it's a suitable alternative? I'll gladly make changes if they'll help. As an aside, I'm wondering whether I should add a white background so that the image is visible for users with dark themes. Thtatithticth (talk) 06:11, 1 April 2020 (UTC)

Thtatithticth, I prefer the first image better, and I guess you could update the image if you decide to put integrate sign or maybe r, v, a, j, s, c, p vector (since it is included in the article) Anyway, I like the image, and I would choose the best image if you suggest more options. Sorry that I couldn't help much with the image. Thanks, Luke Kern Choi 5 (talk) 12:24, 1 April 2020 (UTC)

Thtatithticth, I think your first image is fine. XOR'easter (talk) 16:56, 1 April 2020 (UTC)

I made a slight change and used this. One with integrals is also available, but I think the first is descriptive enough. Regardless, feel free to change it to any of the four. Thtatithticth (talk) 17:47, 1 April 2020 (UTC)

Practical use

The article indicates that higher order derivatives "have little practical use."

Listen beginning at 5:20 of https://www.ted.com/talks/vijay_kumar_robots_that_fly_and_cooperate?language=en

Specifically, these autonomous drones use a "minimum snap trajectory". That's a practical use!

I recommend softening the language in the article and/or pointing to the above (or voluminous other publications from Vijay Kumar at Penn). — Preceding unsigned comment added by 216.15.114.23 (talk) 18:18, 22 February 2021 (UTC)

I was almost exactly one year late, but I think I've addressed this now. Dr. Universe (talk) 17:43, 19 February 2022 (UTC)

I agree that the phrase "little practical use" is too strong. I tried editing the article to soften the language and add some examples of practical uses of fourth-order dynamics, but my edits were flagged as "spam" and reverted. Not sure what to do. — Preceding unsigned comment added by 172.249.153.200 (talk • contribs) 16:37, 8 July 2022 (UTC)

Your edits weren't flagged as spam, but rather as a copyright violation. You can't use work that has been published elsewhere on Wikipedia unless it is properly licensed for us to use it. --Srleffler (talk) 04:46, 10 July 2022 (UTC)

Wiki Education assignment: 4A Wikipedia Assignment

This article was the subject of a Wiki Education Foundation-supported course assignment, between 21 August 2023 and 16 December 2023. Further details are available on the course page. Student editor(s): Elkinhernandes (article contribs). Peer reviewers: Albertoru26, Patthestar12.

— Assignment last updated by Kmijares (talk) 22:40, 15 November 2023 (UTC)

While I don't want to discourage any additions you want to make, this particular page is very obscure and we almost deleted it recently. jerk, the 3rd derivative, is much more useful and interesting. Johnjbarton (talk) 18:00, 1 November 2023 (UTC)

Claims concerning the 7th and 8th derivatives.

In a recent edit @2600:1014:b087:1326:15d:a16c:b952:d188 claimed that even higher derivatives were common. If so there should be reliable references to that effect and in addition the significance of these derivatives needs to be explained. Merely claiming that they are named is not worth putting into the encyclopedia unless they are named as a consequence of their use. Johnjbarton (talk) 16:51, 13 December 2023 (UTC)