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The physical mass of a body as measured by an observer who perceives the body as motionless. Rest mass is an inherent property of elementary particles. Also called invariant mass.
(General Physics) the mass of an object that is at rest relative to an observer. It is the mass used in Newtonian mechanics
the mass of a body as measured when the body is at rest relative to an observer, an inherent property of the body in the theory of relativity.
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|Noun||1.||rest mass - (physics) the mass of a body as measured when the body is at rest relative to an observer, an inherent property of the body|
mass - the property of a body that causes it to have weight in a gravitational field