Convert Feet per Second to Mach 20
Convert Feet per Second (ft/s) to Mach 20 (Ma20) instantly and accurately.
Conversion Formula
Ma20 = ft/s × 4.478533016e-5
About Feet per Second
A foot per second (ft/s) = exactly 0.3048 m/s - the primary speed unit in US ballistics, hydraulics, and gas dynamics. .308 Winchester muzzle velocity ~2,750 ft/s; 9mm pistol 1,200-1,400 ft/s; .50 BMG 2,910 ft/s. Speed of sound at sea level 1,116 ft/s. River channel mean velocities 0.5-6 ft/s; NFPA sprinkler pipe flows also in ft/s. 1 ft/s = 0.3048 m/s = 1.09728 km/h = 60 ft/min.
About Mach 20
Mach 20 ≈ 6,805.8 m/s (24,501 km/h) at ISA sea level - the peak heating regime of ballistic re-entry. Shock layer temperature exceeds 10,000 K; plasma sheath causes radio blackout. Space Shuttle decelerated through Mach 20 at ~75-80 km altitude; Apollo CM hit the atmosphere at ~Mach 36; ICBM warheads re-enter at Mach 18-24. DARPA HTV-2 reached Mach 20 in 2011. 1 Mach 20 = 6,805.8 m/s.
Quick Reference Table
| Feet per Second (ft/s) | Mach 20 (Ma20) |
|---|---|
| 1 ft/s | 4.479 × 10-5 Ma20 |
| 2 ft/s | 8.957 × 10-5 Ma20 |
| 5 ft/s | 0.000223927 Ma20 |
| 10 ft/s | 0.000447853 Ma20 |
| 25 ft/s | 0.00111963 Ma20 |
| 50 ft/s | 0.00223927 Ma20 |
| 100 ft/s | 0.00447853 Ma20 |