Convert Miles per Hour to Feet per Second (mph to fps) instantly using our free online converter. Enter values to view real-time results, formulas, and conversion charts.
Multiply km/h by 0.621 to get mph. Conversely, multiply mph by 1.609 for km/h. Quick rule: 100 km/h ≈ 62 mph. For mental math, divide km/h by 1.6 or multiply mph by 1.6.
At sea level and 20°C, sound travels at 343 m/s = 1,235 km/h = 767 mph = 1,125 ft/s. Mach 1 equals the speed of sound. Speed varies with temperature and medium.
A knot is 1 nautical mile per hour (1.852 km/h). Nautical miles relate to Earth's geometry (1 minute of latitude), making navigation calculations simpler. The term comes from measuring ship speed with a knotted rope.
Speed is a scalar (magnitude only): how fast something moves. Velocity is a vector (magnitude and direction): how fast and which way. A car going 60 mph north has a velocity; 60 mph alone is speed.
Light travels at 299,792,458 m/s exactly (by definition). That's about 300,000 km/s, 186,000 mi/s, or 1.08 billion km/h. Light from the Sun takes about 8 minutes to reach Earth.
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