| 词条 | Pound-foot (torque) |
| 释义 |
| name = Pound-foot | image = | caption = | standard = British Gravitational System, English Engineering Units | quantity = Torque | symbol = lbf∙ft | symbol2 = | extralabel = | extradata = | units1 = SI units | inunits1 = ≈ {{Val|1.355818|ul=Nm}}[1] | units2 = Gravitational metric system | inunits2 = ≈ {{convert|1|lbf.ft|kgf.m|disp=out|sigfig=7}} }} A pound-foot (lbf⋅ft) is a unit of torque (a pseudovector). One pound-foot is the torque created by one pound of force acting at a perpendicular distance of one foot from a pivot point.[2] Conversely one pound-foot is the moment about an axis that applies one pound-force at a radius of one foot. The value in SI units is given by multiplying the following approximate factors: One pound (force) = 4.448 222 newtons[3][4] One foot = 0.3048 m[5] This gives the conversion factor: One pound-foot = {{gaps|1.355|82}} newton metres. The name "pound-foot", intended to minimize confusion with the foot-pound as a unit of work, was apparently first proposed by British physicist Arthur Mason Worthington.[6] However, the torque unit is often still referred to as the foot-pound (ft⋅lbf).[7] Similarly, an inch-pound (though should be more correctly as pound-inch) is the torque of one pound of force applied to one inch of distance from the pivot, and is equal to {{sfrac|1|12}} of a pound-foot. It is commonly used on torque wrenches and torque screwdrivers for setting specific fastener tension. References1. ^{{cite web | title=Appendix B.9: Factors for units listed by kind of quantity or field of science | work=NIST Guide to the SI | date=September 7, 2016 | publisher=National Institute of Standards and Technology | url=https://www.nist.gov/pml/nist-guide-si-appendix-b9-factors-units-listed-kind-quantity-or-field-science | accessdate=2018-07-09 }} {{Classicalmechanics-stub}}{{Engineering-stub}}Foot-pound2. ^{{cite book | title=Today's Technician: Automotive Engine Performance Classroom Manual and Shop Manual | first1=Ken | last1=Pickerill | year=2009 | edition=5th | pages=50–51 | isbn=1111782385 | publisher=Cengage Learning | url=https://books.google.com/books?id=7SEGAAAAQBAJ&pg=PA20 }} 3. ^{{cite web|url=http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdf|author=United States National Bureau of Standards|title=Notices "Refinement of values for the yard and the pound"|date=1959-06-25|accessdate=2006-08-12}} 4. ^{{cite web |last1=Howard Ludwig |title=What is the relation between pounds of force and pounds as a measurement of mass? |url=https://www.quora.com/What-is-the-relation-between-pounds-of-force-and-pounds-as-a-measurement-of-mass |date=Mar 3, 2017}} 5. ^{{citation | contribution=OpenMath Context Dictionaries for SI Quantities and Units | title=Procedings Intelligent Computer Mathematics: 16th Symposium, Calculemus 2009, 8th International Conference, MKM 2009, Grand Bend, Canada, July 6-12, 2009 | first1=Joseph B. | last1=Collins | page=260 | volume=5625 | year=2009 | isbn=3642026141 | publisher=Springer Science & Business Media | editor1-first=Jacques | editor1-last=Carette | editor2-first=Lucas | editor2-last=Dixon | editor3-first=Claudio Sacerdoti | editor3-last=Coen | editor4-first=Stephen | editor4-last=Watt | url=https://books.google.com/books?id=IKNmax4dZ70C&pg=PA260 }} 6. ^{{cite book | author = Arthur Mason Worthington | title = Dynamics of rotation : an elementary introduction to rigid dynamics | year = 1900 | edition = 3rd | publisher = Longmans, Green, and Co. | page = 9 | url = https://archive.org/stream/dynamicsofrotati00wortuoft#page/8/mode/2up}} 7. ^{{cite book | last1 = Erjavec | first1 = Jack | title = Manual Transmissions & Transaxles: Classroom manual | pages = 38 | isbn = 978-1-4354-3933-7 }} 3 : Units of torque|Imperial units|Customary units of measurement in the United States |
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