Mach number
Velocity over soundspeed
Mach number is the ratio of an object's speed to the speed of sound in the surrounding medium.
At Mach 1, something travels exactly at sound speed; above Mach 1 is supersonic.
The jet reached Mach 2.
Named for physicist Ernst Mach, it's fundamental in aerodynamics and determines how air behaves around aircraft at high speeds.
- shock wavePropagating pressure disturbance
- compressibilityVolume reduction potential
- aerodynamicsPhysics of air motion
- transonicNear sound-speed velocity
- sonic boomShockwave's audible crack
velocity · air resistance · speed of sound · sound barrier · fluid mechanics · fighter · afterburner · boundary layer · Bernoulli's principle · boom · aircraft · jet propulsion · jet · turbulence · thrust · nose cone · test pilot · wind tunnel
- aerospaceairplane, helicopter, rocket, rockets, spacecraft
- EponymsDarwinian, Alzheimer's disease, Freudian slip, cardigan, Parkinson's disease
- sound physicssonic boom, sound barrier, subsonic, transonic, shock wave
- Supersonic flightConcorde, sonic boom, sound barrier, SST, afterburner
- Supersonicssonic boom, sound barrier, shock wave, speed of sound, transonic
- aerodynamicsairflow, lift, drag, drag coefficient, turbulence
Mach numbermiles per hour
Speed unit, American roads
kilometers per hour · knots · ground speed · feet per second · airspeed
Mach numbersubsonic
Below sound's speed
incompressible flow · standstill · stationary · stagnant air · walking pace