Unit of Measure Conversions
Velocity (speed) Conversions
Additional Units and Information
| Name | Symbol | Value | Description/Notes |
|---|---|---|---|
| knot | kn; kt | 1,852 metres/hour | International nautical mile per hour |
| Mach number |
M; Ma | Ratio of the speed of an object in a medium to the speed of sound in that medium | |
| c |
2.99792458 x 108 metres/second;
186,282 miles/second |
Speed of light | |
| 331.3 metres/second | Speed of sound in dry (0% humidity) air at 0°C | ||
| 343.3 metres/second | Speed of sound in dry air at 20°C |
Useful Approximations
| Approximation | % Accuracy |
|---|---|
| 60 miles/hour ≈ 100 kilometres/hour | 96.6 |
| 1 knot ≈ ½ metre/second | 97.2 |
| 1 knot ≈ 100 feet/minute | 98.7 |
| Speed of light ≈ 3 x 108 metres/second | 99.9 |