Information: Work equals force times the distance through which the force acts. Force is expressed in newtons (N) and distance is expressed in meters (m). Work is expressed in newton-meters, or the simplification, joules (J). The rate which work is done is called power. Power equals work divided by time. If work is in joules (J) and time is in seconds (s), power is expressed in joules/second, or the simplification watt (W). James Watt was a British scientist who invented the steam engine. To find out how the power of his engine compared to that of a horse, Watt measured how fast an average horse could do work. He found the answer and expressed the amount of the work performed per second as a horsepower. One horsepower is the equivalent of 746 W