In science, dynamics is the study of the motion of bodies under the action of forces. [1] Dynamics, in short, is the science of force and motion. [2]

History
The beginnings of the science of dynamics trace to the 1543 publication of Danish astronomer Nicolaus Copernicus’ famous On the Revolutions of the Celestial Spheres (De revolutionibus orbium coelestium), in which the heliocentric theory was established. The invention of dynamics, as a mathematical science, was initiated by Italian mathematical astronomer Galileo Galilei, with his Dialogue Concerning the Two Chief World Systems (Dialogo sopra i due massimi sistemi del mondo), which compared the then controversial Copernican system with the inconsistencies of the older earth-centric Ptolemaic system. [3]

The science of dynamics was later extended significantly by English physicist Isaac Newton, with his 1687 Principia, who introduced the concepts of force and mass, the laws of motion, and the principle of universal gravitation. [4]

The greatest successor to Newton to extend the subject of dynamics was Italian mathematician Joseph Lagrange who, with his 1788 Analytical Mechanics (Mécanique Analytique), showed that most varied consequences respecting the motions of systems of bodies may be derived from one radical formula. Namely, using a method of generalized co-ordinates, Lagrange showed that if one determines a system’s configuration by a sufficient number of variables whose number is the same as that of the degrees of freedom possessed by the system, then the kinetic and potential energies of the system can be expressed in terms of those variables, and the differential equations of motion thence deduced by simple differentiation.

The work of Lagrange was later extended by Irish mathematical physicist William Hamilton with his two-part 1835 treatise “On a General Method in Dynamics”. [3] Hamilton’s derivation of what he called a “force function” was later referenced in German physicist Rudolf Clausius' 1879 Mechanical Theory of Heat, the founding textbook of the newly emerging science of “thermo-dynamics”. [5]

Societal dynamics
The descriptive phrase cultural dynamics, according to American physical chemist Thomas Wallace, is often employed in tracing cultural transitions, but with rare exceptions tends to be devoid of appropriate models that mention a driving force or an energy source necessary to energize such dynamics. Wallace argues that: [6]

“A thermodynamic-based economic model identifies the dynamics that drive all human existence including the economic, social, and political activities of a society.”

See also
● -dynamic

References
1. Daintith, John. (2005). Oxford Dictionary of Science. Oxford University Press.
2. Earnshaw, Samuel. (1844). Dynamics – or a Treatise on Motion, (title page “Quote” by John Herschel). J. & J. J. Deighton.
3. (a) Hamilton, W.R. (1834). “On a general method in dynamics by which the study of the motions of all free systems of attracting or repelling points is reduced to the search and differentiation of one central relation, or characteristic function.” Philos. Trans. R. Soc. London, 124:247-308.
(b) Hamilton, W.R. (1835). “A second essay on a general method in dynamics.” Philos. Trans. R. Soc. London, 125:95-144.
4. Goodman, Lawrence E., Goodman, Susan, and Warner, William H. (2001). Dynamics, (Historical Introduction). Courier Dover Publications.
5. Clausius, Rudolf. (1879). The Mechanical Theory of Heat, (2nd ed). London: Macmillan & Co.
6. Wallace, Thomas P. (2009). Wealth, Energy, and Human Values: the Dynamics of Decaying Civilizations from Ancient Greece to America (pg. 2). AuthorHouse.