Related Directory Categories
- Mass-media (271)
- Mass Spectrometry (113)
- Mass Sellers (79)
- Radio (67)
- Products and Services (56)
- Masse (53)
- Ziare (51)
- Televiziune (50)
- Mass media (42)
- Instruments (36)
Sources
Help build the largest human-edited directory on the web.
Submit a site - Become an editor
Wikipedia. Licensed under the GNU Free Documentation License.
Are you an expert in this subject? Join the discussion and share your knowledge at Wikipedia.org.
Slug (mass)
From Wikipedia, the free encyclopedia
The slug is an English unit of mass. It is a mass that accelerates by 1 ft/s² when a force of one pound-force (lbf) is exerted on it. Therefore a slug has a mass of about 32.17405 pound-mass or 14.5939 kg.[1]
The slug is part of a subset of coherent units known as the gravitational foot-pound-second system (FPS), one of several such specialized systems of mechanical units developed in the late 19th and the 20th century.
The slug was first used in 1902 by Arthur Mason Worthington (1852–1916) in Dynamics of Rotation (OED), but it didn't see any significant use until decades later. A 1928 textbook says:[2] " 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". The OED also cites a 1935 usage describing the slug as a "paper unit".
Another name for this unit in early literature is the geepound.
The term metric slug appears as a footnote in the 1967 seventh edition of Marks Standard Handbook for Mechanical Engineers. The term is sometimes collapsed to mug and it is also called the TME (German: technische Masseneinheit, technical mass unit). It is the mass that accelerates at 1 m/s² under a force of 1 kgf. Because 1 kgf = 9.80665 N, the metric slug is 9.80665 kilograms. This has also been called the hyl, but there is an alternate definition of the hyl equalling 9.80665 grams which would make the kilohyl equal to the TME. The unit blob is the inch version of slugs (1 lbf·s²/in).
| Systems | Gravitational | Engineering | Absolute | |||
|---|---|---|---|---|---|---|
| Newton’s second law | F = m·a | F = m·a/gc = w·a/g | F = m·a | |||
| Weight of an object | w = m·g | w = m·g/gc | w = m·g | |||
| Units | English | Metric | English | Metric | English | Metric |
| Time | s | s | s | s | s | s |
| Distance | ft | m | ft | m | ft | m |
| Mass | slug | hyl | pound-mass | kilogram | pound | kilogram |
| Force | pound | kilopond | pound-force | kilopond | poundal | newton |
In the film An Officer and a Gentleman Richard Gere plays a trainee naval aviator attending Naval Officer Training School. In one scene his aerodynamics instructor uses "slugs per cubic foot".
- ^ a b Shigley, Joseph E. and Mischke, Charles R. Mechanical Engineering Design, Sixth ed. McGraw Hill, 2006. ISBN 0-07-365939-8.
- ^ Noel Charlton Little, College Physics, Charles Scribner’s Sons, 1928, p. 165
- Newtons, Slugs and Kilograms Force for a detailed mathematical explanation
- Online unit converter