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
Three Laws of Robotics clever enough to comprehend that its actions are for humankind's long-term good. In Jacques Brécard's 1956 French translation entitled "" Baley's thoughts emerge in a slightly different way: Three times during his writing career, Asimov portrayed robots that disregard the Three Laws entirely. The first case was a short-short story entitled "First Law" and is often considered an insignificant "tall tale" or even apocryphal. On the other hand, the short story "Cal" (from the collection "Gold"), told by a first-person robot narrator, features a robot who disregards the Three Laws because he has found something far more important—he wants to