Horsepower is a unit of power that is approximately how much work one horse can do. It is equal to 746 watts . The idea of horsepower was originated by James Watt , who invented the steam engine . Because people used horses to pull carts, it was an amount of energy that could be understood by most people at that time. A human can only maintain about 0.1 horsepower (75 watts), but an engine can maintain much higher than that. Small motors can create 10 horsepower (7.5 kilowatts) while a jet engine can create more than 1,000 horsepower (750 kilowatts).

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