Mass

Mass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. It is a central concept of classical mechanics and related subjects.

Units of mass

In the SI system of units, mass is measured in kilograms (kg). Many other units of mass are also employed, such as: grams (g), metric tons, pounds, ounces, long and short tons, quintals, slugs, atomic mass units, Planck masses, solar masses, and eV/c2.

Related Topics:
SI - Kilogram - Gram - Metric ton - Pound - Ounce - Long - Short ton - Quintal - Slug - Atomic mass unit - Planck mass - Solar mass - EV - C

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The eV/c2 unit is based on the electron volt (eV), which is normally used as a unit of energy. However, because of the relativistic connection between (rest) mass and energy, E = mc2 (see below), it is possible to use any unit of energy as a unit of mass instead. Thus, in particle physics where mass and energy are often interchanged, it is common to use not only eV/c2 but even simply eV as a unit of mass (roughly 1.783 × 10-36 kg).

Related Topics:
Electron volt - Energy - Below - Particle physics

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Because the gravitational acceleration is approximately constant on the surface of the Earth, a unit like the pound is often used to measure either mass or force (e.g. weight), although the pound is officially defined as a unit of mass.

Related Topics:
Gravitational acceleration - Earth - Pound - Force

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For more information on the different units of mass, see Orders of magnitude (mass).

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