Conversion in the opposite direction
The inverse of the conversion factor is that 1 foot per second is equal to 0.0017145 times 640 kilometers per hour.
It can also be expressed as: 640 kilometers per hour is equal to feet per second.
An approximate numerical result would be: six hundred and forty kilometers per hour is about five hundred and eighty-three point two five feet per second, or alternatively, a foot per second is about zero times six hundred and forty kilometers per hour.
 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.