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horsepower,unit of powerpower,
in physics, time rate of doing work or of producing or expending energy. The unit of power based on the English units of measurement is the horsepower, devised for describing mechanical power by James Watt, who estimated that a horse can do 550 ft-lb of work per sec; a
..... Click the link for more information. in the English system of units. It is equal to 33,000 foot-poundsfoot-pound,
abbr. ft-lb, unit of work or energy in the customary English gravitational system; it is the work done or energy expended by a force of 1 pound acting through a distance of 1 foot. It is equal to 1.356 joules.
..... Click the link for more information. per minute or 550 foot-pounds per second or approximately 746 watts. The term horsepower originated with James Watt, who determined by experiment that a horse could do 33,000 foot-pounds of work a minute in drawing coal from a coal pit.
an obsolete subsidiary unit of power. It was first introduced in the 18th century and continues in use in various branches of technology, mainly in automotive engineering. Horsepower is designated as ls. (Russian, loshadinaia sila), PS (German, Pferdestärke), CV (French, cheval-vapeur), and HP or hp (English). In the USSR and certain other countries 1 hp = 75 kilograms-force per m/sec ≈ 735.5 watts (W); in the USA and Great Britain 1 hp = 550 ft.lb/sec ≈ 745.7 W.