Speed Conversion

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Speed Conversion Formulas

1 centimeter/second = 0.01 meter/second

1 foot/second = 0.3048 meter/second

1 inch/second = 0.0254 meter/second

1 kilometer/hour = 0.27777778 meter/second

1 kilometer/second = 1,000 meter/second

1 knot = 0.51444444 meter/second

1 mile/hour = 0.44704 meter/second

1 mile/second = 1,609.344 meter/second

1 millimeter/second = 0.001 meter/second

Notable Speeds

                                       |-----------------------------------------------------|
                                       | meter/second |  kilometer/hour  |     mile/hour     |
|--------------------------------------|--------------|------------------|-------------------|
|Speed of Light [in vacuum]            |  299,792,458 |  1,079,252,848.8 |  670,616,629.3844 |
|--------------------------------------|--------------|------------------|-------------------|
|Speed of Sound [at 15°C in dry air]   |    340.53    |     1225.91      |       761.74      |
|--------------------------------------------------------------------------------------------|

Note: the speeds of sound have been rounded to two decimal digits.

Influence of Temperature on the Speed of Sound

The speed of sound varies depending on the medium the sound waves are propagating in. However, the speed of sound is usually referring to the speed of sound in dry air, which can be calculated by the following equation:

C=(k*R*T)^(1/2)

k (kappa) is the ratio the specific heat of dry air at constant pressure (CP) to the specific heat of dry air at constant volume (CV), approximately equal to 1.402
R is the gas constant for dry air, approximately equal to 287.04 J.kg-1.K-1
T is temperature of the medium in Kelvin

                                   |-----------------------------------------------|
                                   | meter/second |  kilometer/hour  |  mile/hour  |
|----------------------------------|--------------|------------------|-------------|
|Sound Speed [at 0°C in dry air]   |    331.55    |     1,193.57     |    741.65   |
|----------------------------------|--------------|------------------|-------------|
|Sound Speed [at 5°C in dry air]   |    334.57    |     1,204.45     |    748.41   |
|----------------------------------|--------------|------------------|-------------|
|Sound Speed [at 10°C in dry air]  |    337.56    |     1,215.22     |    755.10   |
|----------------------------------|--------------|------------------|-------------|
|Sound Speed [at 15°C in dry air]  |    340.53    |     1,225.91     |    761.74   |
|----------------------------------|--------------|------------------|-------------|
|Sound Speed [at 20°C in dry air]  |    343.47    |     1,236.50     |    768.32   |
|----------------------------------|--------------|------------------|-------------|
|Sound Speed [at 25°C in dry air]  |    346.39    |     1,247.00     |    774.85   |
|----------------------------------|--------------|------------------|-------------|
|Sound Speed [at 30°C in dry air]  |    349.28    |     1,257.41     |    781.32   |
|----------------------------------------------------------------------------------|

Note: all the speeds of sound have been rounded to two decimal digits.

Influence of Humidity on the Speed of Sound

With changes in humidity come changes in k and R and therefore in the speed of sound. However, those changes are small compared to changes in the temperature and will not be calculated in this page.