Definition

1. Noun:
   • The energy equivalent of a body's mass, as described by the theory of relativity: In physics, 'mass energy' refers to the concept that mass itself is a form of energy, as expressed by the famous equation E=mc², where energy (E) equals mass (m) multiplied by the speed of light squared (c²). It is the total energy content inherent in an object's mass.

Examples of Usage

• Noun:
  • The equation E=mc² demonstrates the equivalence of mass energy.
  • In nuclear reactions, a small amount of mass is converted into a vast quantity of other forms of energy, illustrating the principle of mass energy.
  • The total mass energy of a particle includes its rest mass energy and its kinetic energy.

Advanced Usage

• "rest mass energy": The energy equivalent of an object's mass when it is at rest, calculated as E₀=m₀c².
  • The rest mass energy of an electron is approximately 511 keV.
• "mass-energy equivalence": The principle that mass and energy are interchangeable and fundamentally the same entity.
  • Einstein's theory of special relativity introduced the concept of mass-energy equivalence.

Variants and Related Words

• Mass-energy equivalence (n): The principle that mass and energy are different forms of the same thing.
• Rest energy (n): Another term for rest mass energy.

Synonyms

• Mass-energy equivalence: (Conceptual synonym for the principle)
• Rest energy: (Specifically for the energy of a stationary mass)

Related Phrases

(This term is a specific scientific compound noun and is not typically used in phrasal verb constructions.)

Related Idioms

(This is a precise scientific term and is not used in idiomatic expressions.)

Noun

1. (physics) the mass of a body regarded relativistically as energy