With this information, you can calculate the quantity of feet per minute 640 knots is equal to.

¿What is the inverse calculation between 1 foot per minute and 640 knots?

Performing the inverse calculation of the relationship between units, we obtain that 1 foot per minute is 1.5429266e-05 times 640 knots.

Which is the same to say that 640 knots is 64811.899 feet per minute.

Six hundred forty knots equals to sixty-four thousand eight hundred eleven feet per minute. *Approximation

A foot per minute is one times six hundred forty knots. *Approximation