Foot-pound (energy)


The foot-pound force is a unit of work or energy in the engineering and gravitational systems in United States customary and imperial units of measure. It is the energy transferred upon applying a force of one pound-force through a linear displacement of one foot. The corresponding SI unit is the joule.

Usage

The foot-pound is often used to specify the muzzle energy of a bullet in small arms ballistics, particularly in the United States.
"Foot-pound" is also used as a unit of torque. In the United States this is often used to specify, for example, the tightness of a fastener or the output of an engine. Although they are dimensionally equivalent, energy and torque are distinct physical quantities. Both energy and torque can be expressed as a product of a force vector with a displacement vector ; energy is the scalar product of the two, and torque is the vector product.
Although calling the torque unit "pound-foot" has been academically suggested, both are still commonly called "foot-pound" in colloquial usage. To avoid confusion, it is not uncommon for people to specify each as "foot-pound of energy" or "foot-pound of torque" respectively.

Conversion factors

Energy

1 foot pound-force is equivalent to:
1 foot pound-force per second is equivalent to:
Related conversions: