Mach (20°C, 1 atm) to Foot per Minute

Mach number is the ratio of an object's speed to the speed of sound in the surrounding medium. Mach 1 at 20°C, 1 atm equals approximately 343.6 m/s (1,235 km/h).

Mach = velocity ÷ speed_of_sound. At 20°C: Mach 1 = 343.6 m/s. Speed of sound = √(γRT/M) where γ = heat capacity ratio.

To m/s (at 20°C): × 343.6. To km/h (at 20°C): × 1,237. Note: changes with altitude and temperature.

Fighter jets (Mach 1.5–2.5), commercial aircraft (Mach 0.8–0.85), space shuttle reentry (Mach 25), and missile speeds.

Concorde: Mach 2.04. SR-71 Blackbird: Mach 3.3. X-15: Mach 6.7. Meteorites enter at Mach 50+. Subsonic <1, supersonic >1, hypersonic >5.

Thinking Mach is constant — it varies with temperature/altitude. At 30,000 ft, Mach 1 ≈ 295 m/s (colder air = slower sound).

Mach 1 = speed of sound. Below Mach 1 = subsonic. Mach 1–5 = supersonic. Above Mach 5 = hypersonic. It's a ratio, not a fixed speed.

Foot per minute measures distance in feet traveled in one minute. Common in US industrial and HVAC applications.

1 ft/min = 0.00508 m/s = 0.01829 km/h = 0.3048 m/min.

To ft/s: ÷ 60. To m/s: × 0.00508. To mph: ÷ 88.

HVAC duct air velocity (600–2,000 fpm), conveyor belts (50–300 fpm), elevator speeds (200–1,500 fpm), and escalators (90–120 fpm).

Typical HVAC duct: 800–1,200 fpm. High-rise elevator: 1,000 fpm. Airport moving walkway: 140 fpm.

Confusing ft/min with ft/s — ft/min is 60× slower. Mixing fpm with mph.

60 ft/min = 1 ft/s. ~88 ft/min = 1 mph. Essential for HVAC calculations in the US.