Vis viva

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Vis viva (living force) is a historical name for “energy in motion”. It goes back to Gottfried Wilhelm Leibniz and describes a size that is retained in the event of elastic collisions and many other mechanical processes. His formula, however , was what gives a value for the kinetic energy that is 2 times larger according to today's understanding. It was important that the speed was squared, which leads to a scalar quantity and a correct interpretation as a conservation quantity .

In contrast to Leibniz, René Descartes and Isaac Newton held the impulse for the fundamental conserved quantity (Descartes still understood it as a purely scalar, i.e. not as a vector). For Newton, it was not the energy concept that played a central role , but the concept of force (Vis) as the cause of changes in momentum.

Until the 19th century the term living force was used for energy. However, energy considerations only played a greater role in mechanical practice around the middle of the 19th century, encouraged by the development of thermodynamics. In the 18th century there was a dispute among philosophers about the "true" basic quantities of mechanics, for example in Immanuel Kant's book Thoughts of the True Estimation of Living Forces from 1749 (which, however, played no role among the natural scientists and also by the leading contemporary scientists such as Leonhard Euler , to whom Kant wrote in a letter, was ignored), or in Maupertuis' priority dispute over the principle of the smallest effect .

The Vis-Viva equation of celestial mechanics describes the movement or speed of bodies on Kepler orbits as a consequence of energy conservation.

literature

  • Armin Hermann (Ed.): Article Energy. In: Ders .: History of Physics. A – Z (Lexicon of School Physics; Vol. 7). Aulis Verlag, Cologne 1972, ISBN 3-7614-0154-X (2 volumes).
  • Max Jammer , Article Energy in Donald Borchert (Ed.), Encyclopedia of Philosophy, Thomson Gale 2006
  • István Szabó : History of Mechanical Principles, Birkhäuser 1979

Individual evidence

  1. Leibniz, Brevis demonstration erroris memorabilis Cartesii, Acta Eruditorum, 1686
  2. István Szabó , History of Mechanical Principles, p. 78