Equations of motion when masses move according to Newton's law of gravity. In general relativity, rotational motion is described by the relativistic angular momentum tensor, including the spin tensor, which enter the equations of motion under covariant derivatives with respect to proper time. The Mathisson–Papapetrou–Dixon equations describe the motion of spinning objects moving in a gravitational field. Unlike the equations of motion for describing particle mechanics, which are systems of coupled ordinary differential equations, the analogous equations governing the dynamics of waves and fields are always partial differential equations, since the waves or fields are functions of space and time. For a particular
Clarke's three laws his 1995 book "The Vision of the Anointed". The third law has inspired many snowclones and other variations: A of the third law is The third law has been: Clarke's three laws British science fiction writer Arthur C. Clarke formulated three adages that are known as Clarke's three laws, of which the third law is the best known and most widely cited. They were part of his ideas in his extensive writings about the future. These so-called laws include: One account claimed that Clarke's "laws" were developed after the editor of his works in French started numbering the author's assertions.