Slug (unit)

The slug is a derived unit of mass in the weight-based system of measures, most notably within the British Imperial measurement system and in the United States customary measures system. Systems of measure either define mass and derive weights or define a base weight and derive a mass unit. A slug is defined as the mass that is accelerated by 1 ft/s² when a force of one pound (lbf) is exerted on it.

${\displaystyle 1\,{\text{slug}}=1\,{\frac {{\text{lbf}}\cdot {\text{s}}^{2}}{\text{ft}}}\qquad \Longleftrightarrow \qquad 1\,{\text{lbf}}=1\,{\frac {{\text{slug}}\cdot {\text{ft}}}{{\text{s}}^{2}}}}$

One slug has a mass of 32.174049 lb or 7001145939030000000♠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 downward (definition of weight) of approximately 32.2 lbf or 7002143000000000000♠143 N.

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