massMass (symbolized m ) is a dimensionless quantity representing the amount of matter in a particle or object. The standard unit of mass in the International System ( SI ) is the kilogram ( kg ). Mass is measured by determining the extent to which a particle or objectresists a change in its direction or speed when a force is applied. IsaacNewton stated: A stationary mass remains stationary, and a mass in motionat a constant speed and in a constant direction maintains that state ofmotion, unless acted on by an outside force. For a given applied force,large masses are accelerated to a small extent, and small masses are acceleratedto a large extent. The following formula applies: F = ma where F is the applied force in newton s, m is the massof the object or particle in kilograms, and a is the resulting accelerationin meters per second squared. The mass of an object can be calculated ifthe force and the acceleration are known. Mass is not the same thing as weight. Weight has meaning only when anobject having a specific mass is placed in an acceleration field, suchas the gravitational field of the earth. At the earth's surface, a kilogrammass weighs about 2.2 pounds, for example. But on Mars, the same kilogrammass would weigh only about 0.8 pounds, and on Jupiter it would weigh roughly5.5 pounds. When expressing large or small masses, prefix multipliers are used.The table below shows the most common alternative mass units and theirrelationship to the kilogram.
Unit
(and symbol) | To convert to
kilograms, multiply by: | Conversely,
multiply by: | | metric ton (T) | 1000 | 0.001 | | gram (g) | 0.001 | 1000 | | milligram (mg) | 10 -6 | 10 6 | | microgram (µg) | 10 -9 | 10 9 | | nanogram (ng) | 10 -12 | 10 12 | | picogram (pg) | 10 -15 | 10 15 |
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| Last updated on:
Jul 06, 2007 |
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