# "Скорость", "ускорениe", "рывок" - what's next?

As we all know, acceleration is the derivative of velocity, and if we want to introduce how fast acceleration is changing, thus, introducing a second derivative of velocity — this is actually called jerk (or jolt). In Russian it's called "рывок" (I've also come across the term "толчок"), so, we can say that "ускорение ускорения называется рывком".

We can go further and introduce third, fourth and so on derivatives of velocity, each consecutive one being a more exotic beast and used noticeably rarely in calculations. However, they do exist, and, according to Wikipedia, are called in English "jounce" (or "snap"), "flounce" (or "crackle") and "pounce" (or "pop"), respectively.

My question would be — are there any Russian terms that are well-established and commonly acknowledged by the scientific community for third, fourth and fifth derivations of velocity?

• Snap, Crackle and Pop are animated mascots from instant cereal commercials. I think the terms for derivatives of position of order higher than four belong to the same category as the terms of venery, like "embarrassment of pandas" or "array of hedgehogs", which are only used by people with a special understanding of what "being fun at parties" means. They are a thing in English but not in Russian.
– Quassnoi
Commented Feb 18, 2020 at 2:38
• @Quassnoi well, apart from snap, crackle and pop there are jounce, flounce and pounce. Nobody argues that this belongs to very specific lexicon but the question is whether such lexicon exists in Russian. I'm no physicists and not aware of their professional slang - but I do believe that everyone have professional slang.
– shabunc
Commented Feb 18, 2020 at 9:47
• I don't think the terms like these are actually used in sentences not starting with "did you know that …". My point is that Russian, as a rule, does not have a habit of clinging on something that has been used once in an obscure manuscript (or in a joke email). Are you asking for historical curiosities like those or actual, living words? If your question were "what's 10^49 called in Russian", would you rather accept десять в сорок девятой степени or колода по великому счёту?
– Quassnoi
Commented Feb 18, 2020 at 17:20
• @Quassnoi my question is about some exotic terms from physics for concepts that rarely used in calculations and each of them has English-language wiki article (and actually articles in other languages as well). I'd hardly can compare it to a term from obscure manuscript or a clingy joke. In my opinion comparing this terms to 10^49 is also a bit of a stretch.
– shabunc
Commented Feb 18, 2020 at 17:24

Russian physicist here.

No, we only have "скорость" for both speed and velocity (and we literally say "vector speed" (векторная скорость) if we're talking about velocity in a scientific context). And we have "ускорение" for acceleration.

Yep, the Wikipedia says, that the d²v/dt² is a "рывок", but to be honest, I don't remember this term from university courses.

Maybe there are some exotic terms in very narrow areas of physics, but it would be easier to say "производная скорости N-степени".

I'm neither a native speaker nor a physicist, but I can offer some insight and can't resist posting an answer. After all, it is not every day that a mod asks a question :)

First of all, as an important aside, those who say or imply that the derivative of acceleration is never needed in physics should have listened better to their physics teachers at school. Perhaps the most obvious example is the Abraham-Lorentz force. This is the recoil force on an accelerating or decelerating charged particle caused by the particle emitting electromagnetic radiation and is equal to

Q^2 (da/dt)/ (6 π ε0 c^3),

where Q is the particle charge, ε0 is the electric constant, c is the speed of light, and da/dt is the time derivative of the vector of acceleration. You can verify this formula in the Wikipedia article I linked above, and that article explicitly refers to that derivative as to jerk, which is the same term as used by you in your question.

For those who attended school long ago and forgot the basics, the Abraham-Lorentz force is one of the very central things in physics because this is how the classical model of the atom is disproved. Indeed, long time ago people believed that electrons moved around the nucleus just like planets orbit around the Sun, and such a naive view is easily dispelled if you know about the Abraham-Lorentz force. The latter would make the orbiting electrons quickly lose their energy and spiral towards the nucleus. Indeed, an electron orbiting with a constant speed on a circular orbit experiences a centrifugal acceleration, and the vector of that acceleration rotates together with the electron itself, resulting in a non-zero time derivative of that vector. And that derivative is directed against the velocity of the electron. So, according to the above formula, this is where the Abraham-Lorentz force is directed. So you need a quantum theory to explain stable atoms.

To name another example, there is a gravitational force similar to the Abraham-Lorentz force, that is, the recoil force on an accelerating or decelerating astrophysical object caused by the object emitting gravitational waves. And that force is proportional to the time derivative of the vector of acceleration, if my memory serves me well. Our planet is acted on by that force, but doesn't spiral towards the Sun. Why? The force is so weak that its power is comparable to the power of an ordinary electric lamp, which is nothing on the astrophysical scale. And this is why gravitational waves are so hard to detect.

I also vaguely remember my physics teacher telling me that railway track damage is caused by the derivative of the vector of acceleration, but I can't recall why. I hope I am not mixing things up :) But it's because of that, as I'm recalling, that circular portions of a railway track never abruptly join straight portions. Instead, the curvature changes slowly.

So the derivative of acceleration is an important quantity in physics.

Now back to the question itself.

I just asked a guy whom I had helped improve his English in his physics articles. He is a physicist, albeit Japanese, not Russian.

He says that in the scientific community, there are no really established English terms for derivatives of acceleration of any order, so jerk is at best a jargon word used by some physicists working in some very special fields. All other physicists would react to a quantity being called jerk similar to how English speakers would react to girt :)

(Watch the above referenced video fragment, Adam Hills is a genius :) )

Using special terms for the higher-order derivatives of acceleration would be even funnier. If you need to use such a quantity in your physics article, just call that quantity the derivative of acceleration of the corresponding order. If you use any special term instead, you will simply be not understood.

I think it is very reasonable to think that the same applies to Russian, and I found some evidence for that:

(1) I just Googled the exact phrase испытывает рывок, and none or practically none of the search results imply the derivative of acceleration. The intended meaning is always or almost always experiences a jerk as a sudden movement in the most common sense. So if you say испытывает рывок, no one will think you mean the derivative of acceleration.

(2) I managed to find a Russian physics article in which рывок is used as the time derivative of acceleration, but the authors explicitly define рывок in the abstract:

Установлено, что при задании подъемной машине различных скоростей и ускорений амплитуда изменения усилия в канате зависит от частоты вращения подъемной машины и рывка — величины изменения ускорения в единицу времени.

Since the authors had to define рывок in the abstract(!), it stands to reason that рывок isn't a really established term in the Russian physics community.

And if рывок is not an established term, even despite the importance of that quantity in physics, why would the higher-order derivatives have established names?

So the answer to your question seems to be that there are simply no well-established, widely recognizable Russian terms for derivatives of acceleration of any order. You just call them the n-th derivative of acceleration if you want to be understood. Otherwise the reader may very well get an impression that you, as Russians put it, wrote your article по накури :)

To the best of my memory, in my physics classes in university, we never used any special term for derivatives of acceleration; even "рывок" never came up. Instead, they were simply referred to as "first (second, third, etc.) derivative of acceleration".

I don't think there is one because why do you need it?

However, I can see from Wikipedia that Polish has udar, so you can just take it and use удар for the fourth derivative. I don't think they have anything for the fifth, etc. I'd say you don't even need the third derivative because you should move to vectors, for instance, at that point.

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– Quassnoi
Commented Feb 23, 2020 at 14:49