Angular momentum about a fixed rotation axis is moment of inertia times angular velocity.
Difficulty
Intermediate
Read time
5 min
Prerequisites
Basic algebra, consistent units, and the stated model assumptions
Source
OpenStax, College Physics 2e, §10.5 (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.
Angular momentum about a fixed rotation axis is moment of inertia times angular velocity. This scalar relation gives the component along the axis, not a general three-dimensional vector identity for every rigid body.
| Symbol | Meaning | Units |
|---|---|---|
| Angular Momentum | ||
| Moment of Inertia | ||
| Angular Velocity |
Find angular momentum about a shaft.
Supply momentum values for torque-time calculations.
A rotor has moment of inertia 4 kg·m² and angular velocity +3 rad/s. Find its angular momentum about the shaft.
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
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