Jean le Rond d'Alembert in the context of "Physicist"

Denis Diderot (/ˈdiːdəroʊ/; French: [dəni did(ə)ʁo]; 5 October 1713 – 31 July 1784) was a French philosopher, art critic, and writer, best known for serving as co-founder, chief editor, and contributor to the Encyclopédie along with Jean le Rond d'Alembert. He was a prominent figure during the Age of Enlightenment.

Diderot initially studied philosophy at a Jesuit college, then considered working in the church clergy before briefly studying law. When he decided to become a writer in 1734, his father disowned him. He lived a bohemian existence for the next decade. In the 1740s he wrote many of his best-known works in both fiction and non-fiction, including the 1748 novel Les Bijoux indiscrets (The Indiscreet Jewels).

Joseph-Louis Lagrange (born Giuseppe Luigi Lagrangia or Giuseppe Ludovico De la Grange Tournier; 25 January 1736 – 10 April 1813), also reported as Giuseppe Luigi Lagrange or Lagrangia, was an Italian and naturalized French mathematician, physicist and astronomer. He made significant contributions to the fields of analysis, number theory, and both classical and celestial mechanics.

In 1766, on the recommendation of Leonhard Euler and d'Alembert, Lagrange succeeded Euler as the director of mathematics at the Prussian Academy of Sciences in Berlin, Prussia, where he stayed for over twenty years, producing many volumes of work and winning several prizes of the French Academy of Sciences. Lagrange's treatise on analytical mechanics (Mécanique analytique, 4. ed., 2 vols. Paris: Gauthier-Villars et fils, 1788–89), which was written in Berlin and first published in 1788, offered the most comprehensive treatment of classical mechanics since Isaac Newton and formed a basis for the development of mathematical physics in the nineteenth century.

The Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers (French for 'Encyclopedia, or a Systematic Dictionary of the Sciences, Arts and Crafts'), better known as the Encyclopédie (French: [ɑ̃siklɔpedi]), was a general encyclopedia published in France between 1751 and 1772, with later supplements, revised editions, an index, and translations. It had many contributors, known among contemporaries as the Encyclopédistes. It was edited by Denis Diderot and, until 1759, co-edited by Jean le Rond d'Alembert.

The Encyclopédie is most famous for representing the thought of the Enlightenment. According to Diderot in the article "Encyclopédie", the Encyclopédie's aim was "to change the way people think" and to allow people to inform themselves. Diderot hoped the Encyclopédie would disseminate a vast amount of knowledge to the present and future generations. Thus, it is an example of democratization of knowledge, though the high price of the first edition especially (980 livres) prevented it from being bought by much of the middle class.

Peter III Fyodorovich (Russian: Пётр III Фёдорович, romanized: Pyotr III Fyodorovich; 21 February [O.S. 10 February] 1728 – 17 July [O.S. 6 July] 1762) was Emperor of Russia from 5 January 1762 until 9 July of the same year, when he was overthrown by his wife, Catherine II (the Great). He was born in the German city of Kiel as Charles Peter Ulrich of Schleswig-Holstein-Gottorp (German: Karl Peter Ulrich von Schleswig-Holstein-Gottorp), the grandson of Peter the Great and great-grandson of Charles XI of Sweden.

After a 186-day reign, Peter III was overthrown in a palace coup d'état orchestrated by his wife, and soon died under unclear circumstances. The official cause proposed by Catherine's new government was that he died due to hemorrhoids. This explanation was met with skepticism, both in Russia and abroad, with notable critics such as Voltaire and d'Alembert expressing doubt about the plausibility of death from such a condition.

The Encyclopédistes (French: [ɑ̃siklɔpedist]) (also known in British English as Encyclopaedists, or in U.S. English as Encyclopedists) were contributors to the Encyclopédie, the first encyclopedia with signed contributions from numerous collaborators. The Encyclopédie (1751-72) was edited by Jean-Paul De Gua de Malves from 1746 to 1747, co-edited by Denis Diderot and Jean le Rond d'Alembert from 1747 to 1758, and edited by Diderot alone through 1772.

In mathematics, d'Alembert's equation, sometimes also known as Lagrange's equation, is a first order nonlinear ordinary differential equation, named after the French mathematician Jean le Rond d'Alembert. The equation reads as

After differentiating once, and rearranging with ${\displaystyle p=dy/dx}$, we have

D'Alembert's principle, also known as the Lagrange–d'Alembert principle, is a statement of the fundamental classical laws of motion. It is named after its discoverer, the French physicist and mathematician Jean le Rond d'Alembert, and Italian-French mathematician Joseph Louis Lagrange. D'Alembert's principle generalizes the principle of virtual work from static to dynamical systems by introducing forces of inertia which, when added to the applied forces in a system, result in dynamic equilibrium.

D'Alembert's principle can be applied in cases of kinematic constraints that depend on velocities. The principle does not apply for irreversible displacements, such as sliding friction, and more general specification of the irreversibility is required.