relativistic mass

Thân thiện

A scientist explains the concept of relativistic mass on a classroom whiteboard.

Definition

1. Noun:
   • (Physics) The mass of a body in motion relative to an observer: In the theory of special relativity, relativistic mass is the mass of an object as measured by an observer who sees the object moving. It is calculated by multiplying the object's rest mass by the Lorentz factor, which increases as the object's velocity approaches the speed of light.

Usage Examples

• Noun:
  • As a particle accelerates to near-light speeds, its relativistic mass increases significantly.
  • The concept of relativistic mass helps explain why no object with mass can reach the speed of light.

Advanced Usage

• In equations: Relativistic mass (m) is defined by the formula m = m₀ / √(1 - v²/c²), where m₀ is the rest mass, v is the velocity, and c is the speed of light.
  • In the equation, the relativistic mass becomes infinite as velocity (v) approaches the speed of light (c).

Variants and Related Words

• Rest mass (n): The mass of an object when it is at rest relative to an observer. It is an invariant quantity in physics.
  • The electron has a constant rest mass.
• Invariant mass (n): Another term for the rest mass of a system, emphasizing it is the same for all observers.
• Lorentz factor (n): The factor (γ = 1/√(1 - v²/c²)) by which rest mass is multiplied to yield relativistic mass.

Synonyms

• Apparent mass: Sometimes used informally to describe the increased mass measured by a moving observer.
• Inertial mass in motion: A descriptive synonym highlighting the mass's relation to inertia during motion.

Notes on Usage

• Conceptual Note: While useful historically, the term "relativistic mass" is less emphasized in modern physics pedagogy, with a stronger focus on "rest mass" and the concept that mass is an invariant quantity. The increase is often discussed in terms of momentum and energy rather than mass itself.
• Context: This term is used almost exclusively in the context of Einstein's theory of special relativity and high-energy particle physics.

Học thuật

Noun

1. (physics) 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