Jump to content

Slug (unit)

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by QuackOfaThousandSuns (talk | contribs) at 14:50, 30 September 2011 (→Similar units). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

The slug is a unit of mass associated with Imperial units. It is a mass that accelerates by 1 ft/s2 when a force of one pound-force (lbF) is exerted on it.

With standard gravitation gc = 9.80665 m/s2, the international foot of 0.3048 m and the avoirdupois pound of 0.45359237 kg, one slug therefore has a mass of approximately 32.17405 lb or 14.593903 kg.[1] At the surface of the Earth, an object with a mass of 1 slug exerts a force of about 32.17 lbF or 143 N.[2][3]

History

The slug is part of a subset of units known as the gravitational FPS system, one of several such specialized systems of mechanical units developed in the late 19th and the 20th century. Geepound was another name for this unit in early literature.[4]

The name "slug", as a unit of inertia, was coined before 1900 by British physicist Arthur Mason Worthington,[5] but it did not see any significant use until decades later. A 1928 textbook says:

No name has yet been given to the unit of mass and, in fact, as we have developed the theory of dynamics no name is necessary. Whenever the mass, m, appears in our formulae, we substitute the ratio of the convenient force-acceleration pair (w/g), and measure the mass in lbs. per ft./sec.2 or in grams per cm./sec.2.

— Noel Charlton Little, College Physics, Charles Scribner’s Sons, 1928, p. 165.
Three approaches to units of mass and force or weight[6][7]
Base 		Force Weight Mass
2nd law of motion m = ⁠F/a⁠ F = ⁠W ⋅ a/g⁠ F = m ⋅ a
System BG GM EE M AE CGS MTS SI
Acceleration (a) ft/s2 m/s2 ft/s2 m/s2 ft/s2 Gal m/s2 m/s2
Mass (m) slug hyl pound-mass kilogram pound gram tonne kilogram
Force (F),
weight (W) 		pound kilopond pound-force kilopond poundal dyne sthène newton
Pressure (p) pound per square inch technical atmosphere pound-force per square inch standard atmosphere poundal per square foot barye pieze pascal

Similar units

The unit slinch (a portmanteau of the words slug and inch[8]) is an inch version of the slug (1 slinch = 1 lbf·s2/in = 12 slugs).[9] Slang terms for the slinch include the slugette.[10]

References

  1. ^ Shigley, Joseph E. and Mischke, Charles R. Mechanical Engineering Design, Sixth ed, pp. 18–19. McGraw Hill, 2006. ISBN 0-07-365939-8.
  2. ^ Shevell, R.S. Fundamentals of Flight, 2nd ed, p. xix. Prentice-Hall, 1989.
  3. ^ Beckwith, Thomas G., Roy D. Marangoni, et al. Mechanical Measurements, Fifth ed, pp. 34-36. Addison-Wesley Publishing, 1993. ISBN 0-201-56947-7.
  4. ^ [1]. unit2unit.eu
  5. ^ Worthington, Arthur Mason (1900). Dynamics of Rotation: An Elementary Introduction to Rigid Dynamics (3rd ed.). Longmans, Green, and Co. p. 9.
  6. ^ Comings, E. W. (1940). "English Engineering Units and Their Dimensions". Industrial & Engineering Chemistry. 32 (7): 984–987. doi:10.1021/ie50367a028.
  7. ^ Klinkenberg, Adrian (1969). "The American Engineering System of Units and Its Dimensional Constant gc". Industrial & Engineering Chemistry. 61 (4): 53–59. doi:10.1021/ie50712a010.
  8. ^ Miscellaneous
  9. ^ Slug - DiracDelta Science & Engineering Encyclopedia
  10. ^ Celmer, Robert. Notes to Accompany Vibrations II. Version 2.2. 2009.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Slug_(unit)&oldid=453220818"