# Foot-pound

Physical unit
Unit name foot-pound
Unit symbol ${\ displaystyle \ mathrm {ft \ cdot lb}}$
Physical quantity (s) energy
Formula symbol ${\ displaystyle W \, E}$
dimension ${\ displaystyle {\ mathsf {M \; L ^ {2} \; T ^ {- 2}}}}$
system Anglo-American system of measurement
In SI units ${\ displaystyle \ mathrm {1 \, ft \ cdot lb \; \ approx \; 1 {,} 355 \, 817 \, 948 \; J}}$
In CGS units ${\ displaystyle \ mathrm {1 \, ft \ cdot lb \; \ approx \; 13 \, 558 \, 179 {,} 48 \; erg}}$
Derived from Foot , pound
Physical unit
Unit name Pound-foot
Unit symbol ${\ displaystyle \ mathrm {ft \ cdot lb}}$
Physical quantity (s) Torque
Formula symbol ${\ displaystyle M}$
dimension ${\ displaystyle {\ mathsf {M \; L ^ {2} \; T ^ {- 2}}}}$
system Anglo-American system of measurement
In SI units ${\ displaystyle \ mathrm {1 \, ft \ cdot lb \; \ approx \; 1 {,} 355 \, 817 \, 948 \; Nm}}$
In CGS units ${\ displaystyle \ mathrm {1 \, ft \ cdot lb \; \ approx \; 13 \, 558 \, 179 {,} 48 \; dyn \ cdot cm}}$
Derived from Foot , pound

The foot-pound or foot-pound force is a British and American 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 1.355 817 948 331 400 4  J ( Joule ) and corresponds to the energy that has to be applied to lift a body with a mass of one pound by one foot against its weight :

${\ displaystyle {1 \, \ mathrm {ft} \ cdot \ mathrm {lb} = \ mathrm {lb} \ cdot g \ cdot \ mathrm {ft} = 0 {,} 45359237 \, \ mathrm {kg} \ cdot 9 {,} 81 \, {\ frac {\ mathrm {m}} {\ mathrm {s} ^ {2}}} \ cdot 0 {,} 3048 \, \ mathrm {m} = 1 {,} 35581 \ dots \, \ mathrm {kg} {\ frac {\ mathrm {m} ^ {2}} {\ mathrm {s} ^ {2}}} = 1 {,} 355 \, 817 \, 948 \, 331 \ , 400 \, 4 \, \ mathrm {J}}}$

550 foot-pounds per second correspond to one hp (about 745.7 watts).