The word “horsepower” was first used two hundred years ago. James Watt had made the world’’s first widely used ( 11 ) _________. He had no way of telling people exactly how powerful it was, for ( 12 ) _________ there were no units for measuring power.
Watt decided to find out how much work one strong horse could do in (13) _________ He called that unit one horsepower. With this unit he could measure the work his steam engine could do.
He discovered that a horse lift a (14) _________ weight 10 feet in one minute. Because his engine did (15) _________ as much as the horse, Watt called it a ten-horsepower engine.