Newton's laws of motion are for linear motion. Did he also discover the laws of motion for rotation - angular momentum, torque and the moment of inertia; or was this discovered by others?


Jean Buridan (1295-1358), the discoverer/inventor of momentum (impetus), also discussed angular momentum. From Ernest A. Moody's Complete Dictionary of Scientific Biography entry on Buridan:

Buridan’s concept of impetus is further distinguished from the modern inertial concept by the fact that he construes rotational motion at uniform angular velocity as due to a rotational impetus analogous to the rectilinear impetus involved in projectile motion. Galileo did likewise, and was in this respect nearer to Buridan than to Newton. But Buridan makes a striking use of his impetus concept, in its rotational sense [i.e., angular momentum], by arguing that since the celestial spheres posited by the astronomers encounter no external resistance to the rotational movements and have no internal tendency toward a place of rest (such as heavy and light bodies have), their uniform rotational motions are purely inertial and require no causes acting on them to maintain their motions. There is, therefore, no need to posit immaterial intelligences as unmoved movers of the heavenly spheres, in the manner that Aristotle and his commentators supposed. “For it could be said that God, in creating the world, set each celestial orb in motion… and, in setting them in motion, he gave them an impetus capable of keeping them in motion without there being any need of his moving them any more.”5 It was in this way, Buridan adds, that God rested on the seventh day and committed the motions of the bodies he had created to those bodies themselves.

5. Qu. De caelo et mundo II, 22 (1942), 227.

Also, Thomas Bradwardine (d. 1349) appears to have been the first to define angular velocity, which he called velocitas circuitionis; cf. Duhem's Études sur Léonard de Vinci vol. 3, p. 305-306 (p. 219 of the English translation).


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