Projectiles, pendula, and special relativity

TL;DR

This paper explores how flat-earth gravity models in introductory physics relate to accelerated reference frames in special relativity, analyzing projectile and pendulum motion using basic relativistic tools.

Contribution

It provides a simple relativistic description of projectile and pendulum motion driven by earth-surface gravity, connecting classical physics with special relativity.

Findings

Relativistic effects on projectile motion are derived.

Pendulum behavior is analyzed within a relativistic framework.

The approach uses only basic special relativity tools.

Abstract

The kind of flat-earth gravity used in introductory physics appears in an accelerated reference system in special relativity. From this viewpoint, we work out the special relativistic description of a ballistic projectile and a simple pendulum, two examples of simple motion driven by earth-surface gravity. The analysis uses only the basic mathematical tools of special relativity typical of a first-year university course.