One slug has a mass of 32.17405 lbm or 14.593903 kg based on standard gravity, the international foot, and the avoirdupois pound. 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.
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.
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.
|Base||force, length, time||weight, length, time||mass, length, time|
|Force (F)||F = m·a = w·a||F = m·a = w·a||F = m·a = w·a|
|Weight (w)||w = m·g||w = m·g ≈ m||w = m·g|
The slug is listed in the "Regulations under the Weights and Measures (National Standards) Act, 1960". This regulation defines the units of weights and measures, both regular and metric, in Australia.
Similar units 
The blob is the inch version of the slug (1 blob = 1 lbf·s2/in = 12 slugs) or equivalent to 175.126 kg. This unit is also called slinch (a portmanteau of the words slug and inch). Slang terms are slugette, and a snail.
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