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crank

(Encyclopedia)crank, mechanical linkage consisting of a bar attached to a pivot at one of its ends in such a way that it is capable of rotating through a complete circle about the pivot. One of the principal uses o...

Hays, Will H.

(Encyclopedia)Hays, Will H., 1879–1954, American politician and motion-picture executive, b. Sullivan, Ind.; his original name was William Harrison Hays. Hays became active in Indiana political affairs, was chair...

rotary engine

(Encyclopedia)rotary engine, internal-combustion engine whose cycle is similar to that of a piston engine, but which produces rotary motion directly without any conversion from reciprocating motion. A major problem...

Muybridge, Eadweard

(Encyclopedia)Muybridge, Eadweard ĕdˈwərd mīˈbrĭj [key], 1830–1904, English-born photographer and student of animal locomotion. Muybridge changed his name from Edward James Muggeridge. A gifted and obsessed...

Barnard's star

(Encyclopedia)Barnard's star, star with the largest observed proper motion (rate of motion across the sky with respect to other stars); located in the constellation Ophiuchus. The star's large proper motion, 10.28�...

centripetal force and centrifugal force

(Encyclopedia)CE5 Centripetal and centrifugal forces: When a ball is swung in a circle at the end of a string, centripetal and centrifugal forces act as shown above. centripetal force and centrifugal force, act...

fluid mechanics

(Encyclopedia)fluid mechanics, branch of mechanics dealing with the properties and behavior of fluids, i.e., liquids and gases. Because of their ability to flow, liquids and gases have many properties in common not...

Ptolemaic system

(Encyclopedia)Ptolemaic system tŏlˌəmāˈĭk [key], historically the most influential of the geocentric cosmological theories, i.e., theories that placed the earth motionless at the center of the universe with a...

relativity

(Encyclopedia)relativity, physical theory, introduced by Albert Einstein, that discards the concept of absolute motion and instead treats only relative motion between two systems or frames of reference. One consequ...

Gilbreth, Frank Bunker

(Encyclopedia)Gilbreth, Frank Bunker, 1868–1924, b. Fairfield, Me., and his wife, Lillian Moller Gilbreth, 1878–1972, b. Oakland, Calif., pioneering American industrial engineers. He was a largely self-taught e...