Get the details behind our redesign

1.

the mass of a body in motion relative to the observer: it is equal to the rest mass multiplied by a factor that is greater than 1 and that increases as the magnitude of the velocity increases.

Dictionary.com Unabridged

Based on the Random House Dictionary, © Random House, Inc. 2014.

Cite This Source

Based on the Random House Dictionary, © Random House, Inc. 2014.

Cite This Source

relativistic mass in Science

relativistic mass (rěl'ə-tə-vĭs'tĭk) In Special and General Relativity, the observed mass of an object moving with respect to the observer. The relativistic mass is a function of the rest mass and the velocity of the object. Compare rest mass. |

The American Heritage® Science Dictionary

Copyright © 2002. Published by Houghton Mifflin. All rights reserved.

Cite This Source

Copyright © 2002. Published by Houghton Mifflin. All rights reserved.

Cite This Source

Encyclopedia Article for relativistic mass

in the special theory of relativity, the mass that is assigned to a body in motion. In physical theories prior to special relativity, the momentum p and energy E assigned to a body of mass m and velocity v were given by the formulas p = mv and E = E0 + 12mv2, where the value of the "rest energy" E0 was undetermined. In special relativity the corresponding formulas for p and E, respectively, are p = mv/(1 - v2/c2) and E = mc2/(1 - v2/c2), where c equals the speed of light (300,000 kilometres [186,000 miles] per second) and m is the "rest mass" of the body (i.e., its mass as determined when the body is at rest). It is convenient for certain purposes to define the relativistic mass mR of a body by the formula mR = m/(1 - v2/c2). Then, for all velocities we have the simple formulas p = mRv and E = mRc2 for the momentum and energy of a body. The relativistic mass mR becomes infinite as the velocity of the body approaches the speed of light, so, even if large momentum and energy are arbitrarily supplied to a body, its velocity always remains less than c.

Learn more about relativistic mass with a free trial on Britannica.com

Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.

Cite This Source

Cite This Source

17

0

Scrabble
Words With Friends