Английская Википедия:Foot-pound (energy)
Шаблон:Short description Шаблон:Distinguish Шаблон:Refimprove Шаблон:Infobox unit
The foot-pound force (symbol: ft⋅lbf, [1] ft⋅lbf,[2] or ft⋅lb [3]) 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 (lbf) through a linear displacement of one foot. The corresponding SI unit is the joule, though in terms of energy, one joule is not equal to one foot-pound.
Usage
The term foot-pound is also used as a unit of torque (see pound-foot (torque)). In the United States this is often used to specify, for example, the tightness of a fastener (such as screws and nuts) or the output of an engine. Although they are dimensionally equivalent, energy (a scalar) and torque (a Euclidean vector) are distinct physical quantities. Both energy and torque can be expressed as a product of a force vector with a displacement vector (hence pounds and feet); 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.
In small arms ballistics and particularly in the United States, the foot-pound is often used to specify the muzzle energy of a bullet.
Conversion factors
Energy
1 foot pound-force is equivalent to:
- Шаблон:Nowrap joules
- Шаблон:Val ergs
- about Шаблон:Val British thermal units
- Шаблон:Val calories
- Шаблон:Val eV = Шаблон:Val EeV = Шаблон:Val GeV
Power
1 foot pound-force per second is equivalent to:
- 1.3558179483314 watts
- Шаблон:Val horsepower
Related conversions:
- 1 watt ≈ Шаблон:Val ft⋅lbf/min = Шаблон:Val ft⋅lbf/s
- 1 horsepower (mechanical) = 33,000 ft⋅lbf/min = 550 ft⋅lbf/s
See also
References
Шаблон:Imperial units Шаблон:United States Customary Units
- ↑ IEEE Std 260.1™-2004, IEEE Standard Letter Symbols for Units of Measurement (SI Units, Customary Inch-Pound Units, and Certain Other Units)
- ↑ Шаблон:CitationШаблон:Rp
- ↑ Шаблон:Cite book