Mach number

Mach number is a measure of how fast an object is moving relative to the speed of sound in the surrounding medium (usually air). If an object has a Mach number of 1, it is traveling exactly at the speed of sound. If it's less than 1, it's subsonic; if greater than 1, it's supersonic. For example, Mach 0.5 means half the speed of sound, while Mach 2 is twice as fast. This concept helps engineers and pilots understand and predict how objects behave at different speeds, especially as they approach or exceed the speed of sound, affecting aerodynamics and aircraft design.