Mach Cone
supersonic shock waves · Mach angle · sonic boom
Physics: Mach cone half-angle: sinα = 1/M = c/v. At M = 1.5, α = 41.8°; at M = 2, α = 30°. Speed of sound in air: c = 343 m/s at 20°C (c ∝ √T). The shock wave is a pressure discontinuity where wavefronts pile up. Sonic boom energy ~ P²/(ρc). Concorde flew at M = 2.04 (retired 2003). Oblique shocks turn the flow; normal shocks are always M = 1 behind them. In water, Cherenkov radiation is the electromagnetic analogue of Mach waves.