(c) Dr Paul Kinsler. [Acknowledgements & Feedback]

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Mass

Mass is a property of objects, which can be though of as the quantity of matter in them. Alternatively, it can be defined as the measure of an objects resistance to acceleration -- a body with a large mass takes much more energy to accelerate than a lesser one. Moving masses have momentum, and also kinetic- energy. The force of gravity that an object produces is proportional to its mass.

Mass is usually measured in kilograms (kg), although in practise many other units are in use. The rotational counterpart to mass is moment-of-inertia.

Einstein showed that mass can be converted into energy, using the famous formula E=mc^2. Even a tiny amount of mass contains a lot of energy -- in the atom bomb dropped on Hiroshima, only a single gram (10^-3 kg) of matter was converted into energy. However, the energy radiated by the sun is also generated by this conversion, so without this E=mc^2 there would be no life on earth.

XINDEX: proton, particle, neutron, momentum, moment-of-inertia, gravity, force, electron, index-file.

20010720 19990610 19981020 (c) Paul Kinsler

XKEYWORD: mass

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