With this information, you can calculate the quantity of feet per second 644 knots is equal to.
¿What is the inverse calculation between 1 foot per second and 644 knots?
Performing the inverse calculation of the relationship between units, we obtain that 1 foot per second is 0.0009200059 times 644 knots.
Which is the same to say that 644 knots is 1086.9495 feet per second.
Six hundred forty-four knots equals to one thousand eighty-six feet per second. *Approximation
A foot per second is zero times six hundred forty-four knots. *Approximation