One horsepower (1 hp) is the unit of power based on the work that a horse can do in one second. this is defined, in english units, as a force of 550 lb that can move an object 1 foot in 1 s. in si, 1 hp equals 745.7 w, or 745.7 j of work delivered in 1 s. suppose you have a horse that delivers 745.7 w of power, but that it does the work in only 0.55 s. how much work has this horse done?