Mach Cone
Definition
The conical shock wave produced by a supersonic projectile; its half-angle is determined by sin(alpha) = c/v where c is the speed of sound and v is the projectile speed.
- Cause
- Supersonic projectile shock wave
- Shape
- Cone
- Formula
- sin(alpha) = c / v
- Relevance
- Gunshot acoustic trajectory reconstruction
Common questions
Why does the Mach cone matter in a gunshot recording?+
A recording that captures the sharp crack of the Mach cone in addition to the muzzle blast can help investigators estimate the bullet's trajectory relative to the microphone, since the cone's geometry depends on the bullet's speed and path.
Does every gunshot produce a Mach cone?+
No, only when the projectile itself travels faster than the local speed of sound. Subsonic ammunition, or a bullet that has slowed below the speed of sound before passing a given point, will not produce this shock-wave signature there.
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