Pound-foot (torque): Difference between revisions
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The value in [[Système International]] (SI) units is given by multiplying the following exact factors: |
The value in [[Système International]] (SI) units is given by multiplying the following exact factors: |
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:One [[pound (mass)]] = {{val|0.45359237|ul=kilograms}}<ref name="NIST">{{Cite |last=Butcher |first=Kenneth |title=The International System of Units (SI) – Conversion Factors for General Use |date=May 2006 |work=NIST Special Publication 1038 |url=https://www.govinfo.gov/content/pkg/GOVPUB-C13-f10c2ff9e7af2091314396a2d53213e4/pdf/GOVPUB-C13-f10c2ff9e7af2091314396a2d53213e4.pdf |archive-url=https://web.archive.org/web/20230530211151/https://www.govinfo.gov/content/pkg/GOVPUB-C13-f10c2ff9e7af2091314396a2d53213e4/pdf/GOVPUB-C13-f10c2ff9e7af2091314396a2d53213e4.pdf |archive-date=2023-05-30 |url-status=live |last2=Crown |first2=Linda |last3=Gentry |first3=Elizabeth J.}}</ref> |
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:One [[pound (mass)]] = {{val|0.45359237|ul=kilograms}}<ref name=NGS>{{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|access-date=2006-08-12}}</ref><ref name=":0">{{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}}</ref> |
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:[[Standard gravity]] = 9.80665 m/s<sup>2</sup><ref name=" |
:[[Standard gravity]] = 9.80665 m/s<sup>2</sup><ref name="NIST" /> |
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:One [[Foot (unit)|foot]] = 0.3048 m<ref name=" |
:One [[Foot (unit)|foot]] = 0.3048 m<ref name="NIST" /> |
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| contribution=OpenMath Context Dictionaries for SI Quantities and Units |
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| title=Intelligent Computer Mathematics: 16th Symposium, Calculemus 2009, 8th International Conference, MKM 2009, Grand Bend, Canada, July 6-12, 2009 Proceedings |
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| first1=Joseph B. | last1=Collins |
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| page=260 | volume=5625 | year=2009 | isbn=978-3642026140 |
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| publisher=Springer Science & Business Media |
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| editor1-first=Jacques | editor1-last=Carette |
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| editor2-first=Lucas | editor2-last=Dixon |
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| editor3-first=Claudio Sacerdoti | editor3-last=Coen |
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| editor4-first=Stephen | editor4-last=Watt |
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| url=https://books.google.com/books?id=IKNmax4dZ70C&pg=PA260 }}</ref> |
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This gives the exact conversion factor: |
This gives the exact conversion factor: |
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Revision as of 08:51, 24 April 2024
| pound-foot | |
|---|---|
| Unit system | British Gravitational System, English Engineering Units |
| Unit of | Torque |
| Symbol | lbf⋅ft, lb-ft |
| Conversions | |
| 1 lbf⋅ft in ... | ... is equal to ... |
| SI units | ≈ 1.355818 N⋅m[1] |
| Gravitational metric system | ≈ 0.1382550 kgf⋅m |
A pound-foot (lb⋅ft), abbreviated from pound-force foot (lbf · ft), is a unit of torque representing one pound of force acting at a perpendicular distance of one foot from a pivot point.[2] Conversely one foot pound-force (ft · lbf) is the moment about an axis that applies one pound-force at a radius of one foot.
Unit
The value in Système International (SI) units is given by multiplying the following exact factors:
- One pound (mass) = 0.45359237 kilograms[3]
- Standard gravity = 9.80665 m/s2[3]
This gives the exact conversion factor:
- One pound-foot = 1.3558179483314004 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.[4]
Despite this, in practice torque units are commonly called the foot-pound (denoted as either lb-ft or ft-lb) or the inch-pound (denoted as in-lb).[5][6] Practitioners depend on context and the hyphenated abbreviations to know that these refer to neither energy nor moment of mass (as the symbol ft-lb rather than lbf-ft would imply).
Similarly, an inch-pound (or pound-inch) is the torque of one pound of force applied to one inch of distance from the pivot, and is equal to 1⁄12 lbf⋅ft (0.1129848 N⋅m). It is commonly used on torque wrenches and torque screwdrivers for setting specific fastener tension.
See also
- Kilogram metre (torque) (kgf⋅m)
References
- ^ "Appendix B.9: Factors for units listed by kind of quantity or field of science". NIST Guide to the SI. National Institute of Standards and Technology. September 7, 2016. Retrieved 2018-07-09.
- ^ Pickerill, Ken (2009). Today's Technician: Automotive Engine Performance Classroom Manual and Shop Manual (5th ed.). Cengage Learning. pp. 50–51. ISBN 978-1111782382.
- ^ a b c Butcher, Kenneth; Crown, Linda; Gentry, Elizabeth J. (May 2006), "The International System of Units (SI) – Conversion Factors for General Use" (PDF), NIST Special Publication 1038, archived (PDF) from the original on 2023-05-30
- ^ Arthur Mason Worthington (1900). Dynamics of rotation : an elementary introduction to rigid dynamics (3rd ed.). Longmans, Green, and Co. p. 9.
- ^ "Dial Torque Wrenches from Grainger". Grainger. 2020. In most US industrial settings, the torque ranges are given in ft-lb rather than lbf-ft.
- ^ Erjavec, Jack (22 January 2010). Manual Transmissions & Transaxles: Classroom manual. p. 38. ISBN 978-1-4354-3933-7.