Foot-pound (energy)
Foot-pound | |
---|---|
Unit system | English Engineering units and British Gravitational System |
Unit of | Energy |
Symbol | ft⋅lbf |
Unit conversions | |
1 ft⋅lbf in ... | ... is equal to ... |
SI units | 1.355818 J |
CGS units | 13,558,180 erg |
The foot pound-force (symbol: ft⋅lbf or ft⋅lb)^{[1]} 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.
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 sometimes also used as a unit of torque (see pound-foot (torque)). In the United States this unit is often used to specify, for example, the tightness of a bolt or the output of an engine. Although they are dimensionally equivalent, energy (a scalar) and torque (a 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.
Conversion factors
Energy
1 foot pound-force is equivalent to:
- 1.355 817 948 331 400 4 joules
- 558179.483314004 13ergs
- about ×10^{−3} 1.285British thermal units
- 832 0.323calories
- 238×10^{+18} 8.462eV = 238 8.462EeV = 238×10^{+9} 8.462GeV
Power
1 foot pound-force per second is equivalent to:
- 1.355817948 watts
- 18×10^{−3} 1.8horsepower
Related conversions:
- 1 watt ≈ 72896 ft⋅lbf/min = 44.253562149333 ft⋅lbf/s 0.737
- 1 horsepower (mechanical) = 33,000 ft⋅lbf/min = 550 ft⋅lbf/s
See also
References
- ^ Budynas, Richard G.; Nisbett, J. Keith (2014-01-27). Mechanical Engineering Design. McGraw Hill Education. ISBN 978-0073529288. (Subscription required (help)).
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