# sound barrier

> obstacle to achieving supersonic speed

**Wikidata**: [Q1031651](https://www.wikidata.org/wiki/Q1031651)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Sound_barrier)  
**Source**: https://4ort.xyz/entity/sound-barrier


## References

1. Freebase Data Dumps. 2013
2. Quora