With this information, you can calculate the quantity of feet per second 421 knots is equal to.

¿What is the inverse calculation between 1 foot per second and 421 knots?

Performing the inverse calculation of the relationship between units, we obtain that 1 foot per second is 0.0014073249 times 421 knots.

Which is the same to say that 421 knots is 710.56795 feet per second.

Four hundred twenty-one knots equals to seven hundred ten feet per second. *Approximation

A foot per second is zero times four hundred twenty-one knots. *Approximation