Relativistic momentum includes the Lorentz factor in addition to invariant mass and velocity.
Difficulty
Intermediate
Read time
5 min
Prerequisites
Basic algebra, consistent units, and the stated model assumptions
Source
OpenStax, College Physics 2e, §28.5 (Paul Peter Urone and Roger Hinrichs)OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example. The textbook section reference was corrected.
Relativistic momentum includes the Lorentz factor in addition to invariant mass and velocity. It approaches the classical result at low speed but grows strongly as speed approaches c.
| Symbol | Meaning | Units |
|---|---|---|
| Momentum | ||
| Invariant (rest) mass | ||
| Velocity | ||
| Speed of Light |
Find momentum beyond the classical approximation.
Supply momentum values for relativistic conservation calculations.
A particle of rest mass 1.00 kg moves at the listed positive speed. Find its relativistic momentum.
OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example. The textbook section reference was corrected.
Assumptions
FormuLab is a study reference. Verify formulas, units, assumptions, and course-specific conventions before relying on them.
© 2026 FormuLab. All rights reserved.