An Improved Inertia Principle

TL;DR

This paper revises the classical Inertia Principle for relativistic systems with spin, proposing that a modified center of mass and spin, rather than the traditional center of mass, exhibits inertial behavior.

Contribution

It introduces a new formulation of the Inertia Principle accounting for spin, altering the understanding of inertial motion in relativistic systems.

Findings

Conservation of total angular momentum implies a modified inertial center of mass and spin.

The traditional statement of the Principle of Inertia is revised for relativistic systems with spin.

A new inertial behavior is identified for the combined center of mass and spin.

Abstract

We show that for isolated relativistic systems with spin the conservation of total angular momentum implies that, instead of the center of mass, it is a modified center of mass and spin which behaves inertially. This requires a change in the the statement of the Principle of Inertia.