# rapidity

> physical quantity, defined as inverse hyperbolic tangent of speed (divided by the speed of light)

**Wikidata**: [Q1366833](https://www.wikidata.org/wiki/Q1366833)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Rapidity)  
**Source**: https://4ort.xyz/entity/rapidity


## References

1. Freebase Data Dumps. 2013
2. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)