In aerodynamics, hypersonic flow generally begins above which Mach number?

A. unity

B. Mach 5

C. greater than unity

D. greater than 2

E. greater than 10

Explanation

Hypersonic flow is generally defined as flight faster than Mach 5, meaning more than five times the local speed of sound. The Mach number compares an object's speed with the local speed of sound.

Source

NASA — Hypersonics

Answer verified on 2026-09-12

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