An equation derived from Einstein's theory of Special Relativity expressing the relationship between the mass and energy of objects with mass. The equation is E = mc2, where E is the energy of the object in joules, m is its relativistic mass in kilograms, and c is the speed of light (approximately 3 X 108 meters per second). Mass-energy equivalence entails that the total mass of a system may change, although the total energy and momentum remain constant; for example, the collision of an electron and a proton annihilates the mass of both particles, but creates energy in the form of photons. The discovery of mass-energy equivalence was essential to the development of theories of atomic fission and fusion reactions.
CAN YOU GUESS THESE WORDS FROM AROUND THE US?
American English is not always as it appears to be ... get to know regional words in this quiz!
Question 1 of 10
A bet is synonymous with a wager, but what does it mean in New York?
Words nearby mass-energy equivalence
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.