Tennis racket theorem: Difference between revisions

Revision as of 03:19, 19 December 2021

Revision as of 04:39, 17 January 2022

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[[File:tennis_racket_theorem.ogv|thumb|upright=1.5|Composite video of a tennis racquet rotated around the three axes – the intermediate one flips from the light edge to the dark edge]]

[[File:Théorie Nouvelle de la Rotation des Corps.jpg|thumb|Title page of "Théorie Nouvelle de la Rotation des Corps", 1852 printing]]

The '''tennis racket theorem''' or '''intermediate axis theorem''' is a result in [[classical mechanics]] describing the movement of a [[rigid body]] with three distinct [[principal moments of inertia]]. It is also dubbed the '''Dzhanibekov effect''', after [[Soviet Union|Soviet]] [[cosmonaut]] [[Vladimir Dzhanibekov]] who noticed one of the theorem's [[logical consequence]]s while in space in 1985<ref>[http://oko-planet.su/science/sciencehypothesis/15090-yeffekt-dzhanibekova-gajka-dzhanibekova.html Эффект Джанибекова (гайка Джанибекова)], 23 July 2009 {{in lang|ru}}. The software can be downloaded [http://live.cnews.ru/forum/index.php?s=5091d296ac0d22ad6b6e9712f3b0edbe&act=Attach&type=post&id=87112 from here]</ref> although the effect was already known for at least 150 years before that.<ref>Poinsot (1834) [https://archive.org/details/thorienouvelled00poingoog/page/n9 ''Theorie Nouvelle de la Rotation des Corps''], Bachelier, Paris</ref><ref>{{cite avAV media|publisher = Veritasium | title = The Bizarre Behavior of Rotating Bodies, Explained | date = September 19, 2019 | url = https://www.youtube.com/watch?v=1VPfZ_XzisU | access-date = February 16, 2020 | people = [[Derek Muller]]}}</ref>

The theorem describes the following effect: rotation of an object around its first and third [[Moment of inertia#Principal axes|principal axes]] is stable, while rotation around its second principal axis (or intermediate axis) is not.

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==External links==

* {{cite web|url=https://www.youtube.com/watch?v=4dqCQqI-Gis|title=Slow motion Dzhanibekov effect demonstration with table tennis rackets|first=|last=Dan Russell|date=5 March 2010|publisher=|accessdate=2 February 2017|via=YouTube}}

* {{cite web|url=https://www.youtube.com/watch?v=L2o9eBl_Gzw|title=Dzhanibekov effect demonstration|first=|last=zapadlovsky|date=16 June 2010|publisher=|accessdate=2 February 2017|via=YouTube}} on [[Mir]] [[International Space Station]]

* {{cite web|url=https://www.youtube.com/watch?v=VHNvzXy-Iqs|title=Djanibekov effect modeled in Mathcad 14|first=|last=Viacheslav Mezentsev|date=7 September 2011|publisher=|accessdate=2 February 2017|via=YouTube}}<!--Modeling in software of the Djanibekov effect with Mathcad 14 -->

*[[Louis Poinsot]], [https://catalog.hathitrust.org/Record/100228096 Théorie nouvelle de la rotation des corps], Paris, Bachelier, 1834, 170 p. {{OCLC| 457954839}} : historically, the first mathematical description of this effect.

*{{Cite web|last=|first=|date=|title=Ellipsoids and The Bizarre Behaviour of Rotating Bodies|url=https://www.youtube.com/watch?v=l51LcwHOW7s|url-status=live|archive-url=|archive-date=|access-date=|website=[[YouTube]]}} - intuitive video explanation by [[Matt Parker]]

[[Category:Classical mechanics]]