With this information, you can calculate the quantity of feet per second 399 miles per hour is equal to.

¿What is the inverse calculation between 1 foot per second and 399 miles per hour?

Performing the inverse calculation of the relationship between units, we obtain that 1 foot per second is 0.0017088175 times 399 miles per hour.

Which is the same to say that 399 miles per hour is 585.2 feet per second.

Three hundred ninety-nine miles per hour equals to five hundred eighty-five feet per second. *Approximation

A foot per second is zero times three hundred ninety-nine miles per hour. *Approximation