638 kilometers per hour in feet per second

Conversion

638 kilometers per hour is equivalent to 581.437736949548 feet per second.^[1]

Conversion in the opposite direction

The inverse of the conversion factor is that 1 foot per second is equal to 0.00171987460815047 times 638 kilometers per hour.

It can also be expressed as: 638 kilometers per hour is equal to $\frac{1}{0.00171987460815047}$ feet per second.

Approximation

An approximate numerical result would be: six hundred and thirty-eight kilometers per hour is about five hundred and eighty-one point four four feet per second, or alternatively, a foot per second is about zero times six hundred and thirty-eight kilometers per hour.

Units involved

This is how the units in this conversion are defined:

Kilometers Per Hour

"The kilometer per hour is a unit of speed, expressing the number of kilometres travelled in one hour. The unit symbol is km/h. Worldwide, it is the most commonly used unit of speed on road signs and car speedometers."

Wikipedia page of kilometers per hour

Feet Per Second

'The foot per second (plural feet per second) is a unit of both speed (scalar) and velocity (vector quantity, which includes direction). It expresses the distance in feet (ft) traveled or displaced, divided by the time in seconds (s, or sec). The corresponding unit in the International System of Units (SI) is the metre per second.Abbreviations include ft/s, ft/sec and fps, and the rarely used scientific notation ft s−1.'

Wikipedia page of feet per second

Footnotes

[1] The precision is 15 significant digits (fourteen digits to the right of the decimal point).

Results may contain small errors due to the use of floating point arithmetic.