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rest mass
noun
: the mass of a body exclusive of additional mass the body acquires by its motion according to the theory of relativity
Examples of rest mass in a Sentence
Recent Examples on the Web
The way, in modern physics (i.e., physics according to the Standard Model) that particles acquire a rest mass is through the Higgs mechanism.
—Big Think, 18 June 2024
All these experiments measure energy, but that's pretty much the same as the rest mass of the particle.
—Phil Plait, Discover Magazine, 13 Dec. 2011
When the temperature of the Universe drops below a certain, critical threshold — a threshold set by the rest mass of each particle — fewer and fewer collisions occur that have enough energy to allow for creation to be a possibility.
—Ethan Siegel, Forbes, 2 Sep. 2021
While rest mass energy, gravitational potential energy, and kinetic energy are all concepts that work perfectly well with Newtonian mechanics and gravitation, the idea of gravitation radiation is inherently novel in Einstein’s General Relativity.
—Ethan Siegel, Forbes, 5 May 2021
The Higgs symmetry was restored early on, and so none of the Standard Model particles possessed a rest mass prior to that time.
—Ethan Siegel, Forbes, 21 Apr. 2021
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Word History
First Known Use
1914, in the meaning defined above
Dictionary Entries Near rest mass
Cite this Entry
“Rest mass.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rest%20mass. Accessed 26 Nov. 2024.
More from Merriam-Webster on rest mass
Britannica.com: Encyclopedia article about rest mass
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