You may have heard of horse power but you may not know what it means (obviously otherwise you wouldn't have clicked here) the term horse power was invented by James Watt (famous for the watt e.g. 60 watt light bulb) its original propose was for coal mining. The miners would use ponies to lift coal in the mines, so James Watt wanted to figure out how much work one pony could do. He found out that the average amount that a pony could do in one minute was 22,000 foot-pounds of work. Then he increased it by 50% and got 33,000 foot pounds of work per minute.