Foot-pound (energy)
The foot-pound or foot-pound force is a British and US unit of both energy and torque (there also pound-foot). The unit symbol is ft-lb or ft-lbf, also lbf-ft.
One foot-pound is exactly equal to 1.355 817 948 331 400 4 J (joules) and is equal to the energy required to lift a body with a mass of one pound by one foot against its weight force:
550 foot-pounds per second equals one hp (about 745.7 watts).