Editing Angular momentum (section)

=== After Newton ===
[[Leonhard Euler]], [[Daniel Bernoulli]], and [[Patrick d'Arcy]] all understood angular momentum in terms of conservation of [[areal velocity]], a result of their analysis of Kepler's second law of planetary motion. It is unlikely that they realized the implications for ordinary rotating matter.<ref>see {{cite web
|url=http://weatherglass.de/PDFs/Angular_momentum.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://weatherglass.de/PDFs/Angular_momentum.pdf |archive-date=2022-10-09 |url-status=live
|last=Borrelli
|first=Arianna
|date=2011
|title=Angular momentum between physics and mathematics}} for an excellent and detailed summary of the concept of angular momentum through history.</ref>

In 1736 Euler, like Newton, touched on some of the equations of angular momentum in his ''[[Mechanica]]'' without further developing them.<ref>
{{cite web
|url=http://www.17centurymaths.com/contents/mechanica1.html
|title=Euler : Mechanica Vol. 1
|last=Bruce
|first=Ian
|date=2008
}}</ref>

Bernoulli wrote in a 1744 letter of a "moment of rotational motion", possibly the first conception of angular momentum as we now understand it.<ref>{{cite web
|url=http://eulerarchive.maa.org/correspondence/letters/OO0153.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://eulerarchive.maa.org/correspondence/letters/OO0153.pdf |archive-date=2022-10-09 |url-status=live
|title=Euler's Correspondence with Daniel Bernoulli, Bernoulli to Euler, 04 February, 1744|website=The Euler Archive}}</ref>

In 1799, [[Pierre-Simon Laplace]] first realized that a fixed plane was associated with rotation—his ''[[invariable plane]]''.

[[Louis Poinsot]] in 1803 began representing rotations as a line segment perpendicular to the rotation, and elaborated on the "conservation of moments".

In 1852 [[Léon Foucault]] used a [[gyroscope]] in an experiment to display the Earth's rotation.

[[William John Macquorn Rankine|William J. M. Rankine's]] 1858 ''Manual of Applied Mechanics'' defined angular momentum in the modern sense for the first time:<blockquote>...&nbsp;a line whose length is proportional to the magnitude of the angular momentum, and whose direction is perpendicular to the plane of motion of the body and of the fixed point, and such, that when the motion of the body is viewed from the extremity of the line, the radius-vector of the body seems to have right-handed rotation.</blockquote>In an 1872 edition of the same book, Rankine stated that "The term ''angular momentum'' was introduced by Mr. Hayward,"<ref>{{cite book
|last1 = Rankine
|first1 = W. J. M.
| title = A Manual of Applied Mechanics
|edition=6th
|publisher = Charles Griffin and Company, London
|url=https://books.google.com/books?id=u9UKAQAAIAAJ
|date=1872|page= 506|via=Google books}}</ref> probably referring to R.B. Hayward's article ''On a Direct Method of estimating Velocities, Accelerations, and all similar Quantities with respect to Axes moveable in any manner in Space with Applications,''<ref name="Hayward">{{cite journal
|last1 = Hayward
|first1 = Robert B.
|title = On a Direct Method of estimating Velocities, Accelerations, and all similar Quantities with respect to Axes moveable in any manner in Space with Applications
|journal = Transactions of the Cambridge Philosophical Society
|date=1864
|volume=10
|pages = 1
|url=https://books.google.com/books?id=Yx1YAAAAYAAJ|bibcode=1864TCaPS..10....1H}}</ref> which was introduced in 1856, and published in 1864. Rankine was mistaken, as numerous publications feature the term starting in the late 18th to early 19th centuries.<ref>see, for instance, {{cite journal
|last1 = Gompertz
|first1 = Benjamin
|title = On Pendulums vibrating between Cheeks
|journal = The Journal of Science and the Arts
|date=1818
|volume=III
|number=V
|page=17
|url=https://books.google.com/books?id=ANE4AAAAMAAJ|via=Google books}}; {{cite book
|last1 = Herapath
|first1 = John
|title = Mathematical Physics
|publisher = Whittaker and Co., London
|date=1847
|page=56
|url=https://books.google.com/books?id=nH0tAAAAYAAJ|via=Google books}}</ref> However, Hayward's article apparently was the first use of the term and the concept seen by much of the English-speaking world. Before this, angular momentum was typically referred to as "momentum of rotation" in English.<ref>see, for instance, {{cite journal
|last1 = Landen
|first1 = John
|title = Of the Rotatory Motion of a Body of any Form whatever
|journal = Philosophical Transactions
|date=1785
|volume=LXXV
|number=I
|pages=311–332
|doi=10.1098/rstl.1785.0016 |s2cid = 186212814
}}</ref>