Equations of motion modification consistent with conservation of momentum, see variable-mass system. It may be simple to write down the equations of motion in vector form using Newton's laws of motion, but the components may vary in complicated ways with spatial coordinates and time, and solving them is not easy. Often there is an excess of variables to solve for the problem completely, so Newton's laws are not always the most efficient way to determine the motion of a system. In simple cases of rectangular geometry, Newton's laws work fine in Cartesian coordinates, but in other coordinate systems can become dramatically complex. The
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