August 1, 2005
|Equations in physics and astronomy use the International System of Units, or SI. According to SI, the speed of light, c, is measured in meters per second, or m/s, as are all velocity measurements. Mass, m, is measured in kilograms, or kg. Energy, E, is in joules, or J. Joules are a derived SI unit, from base units kg, m, and s. The definition of a joule is kg*(m/s)2, which is not surprisingly the definition of Einstein's famous equation. In more familiar terms, a joule is the work done to produce 1 watt for 1 second.|
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