stationary conditions
41Calculus of variations — is a field of mathematics that deals with extremizing functionals, as opposed to ordinary calculus which deals with functions. A functional is usually a mapping from a set of functions to the real numbers. Functionals are often formed as definite …
42Speeds and feeds — A line drawing showing some basic concepts of speeds and feeds in the context of lathe work. The angular velocity of the workpiece (rev/min) is called the spindle speed by machinists. Its tangential linear equivalent at the tool cutter interface… …
43celestial mechanics — the branch of astronomy that deals with the application of the laws of dynamics and Newton s law of gravitation to the motions of heavenly bodies. [1815 25] * * * Branch of astronomy that deals with the mathematical theory of the motions of… …
44commercial fishing — Introduction the taking of fish and other seafood and resources from oceans, rivers, and lakes for the purpose of marketing them. Fishing is one of the oldest employments of humankind. Ancient heaps of discarded mollusk shells (shell… …
45g-force — This article is about a type of acceleration. For other uses, see G force (disambiguation). This top fuel dragster can accelerate from zero to 160 kilometres per hour (100 mph) in 0.86 seconds. This is a horizontal acceleration of 5.3 g …
46Surface weather analysis — A surface weather analysis is a special type of weather map that provides a view of weather elements over a geographical area at a specified time based on information from ground based weather stations. [ Air Apparent: How Meteorologists Learned… …
47Spirit rover — (MER A) Artist s concept of Rover on Mars Operator NASA Mission type Rover Launch date …
48Path integral formulation — This article is about a formulation of quantum mechanics. For integrals along a path, also known as line or contour integrals, see line integral. The path integral formulation of quantum mechanics is a description of quantum theory which… …
491988 Pacific hurricane season — Infobox hurricane season Basin=EPac Year=1988 Track=1988 Pacific hurricane season map.png First storm formed=June 15, 1988 Last storm dissipated=November 2, 1988 Strongest storm name=Hector Strongest storm winds=125 Strongest storm pressure=935… …
50Reaction–diffusion system — Reaction–diffusion systems are mathematical models which explain how the concentration of one or more substances distributed in space changes under the influence of two processes: local chemical reactions in which the substances are transformed… …
