21 feet per second in miles per hour
Conversion
21 feet per second is equivalent to 14.3181818181818 miles per hour.[1]
![21 feet per second is equivalent to 14.3181818181818 miles per hour](/images/21_fps_in_mph.jpg)
Conversion in the opposite direction
The inverse of the conversion factor is that 1 mile per hour is equal to 0.0698412698412698 times 21 feet per second.
It can also be expressed as: 21 feet per second is equal to miles per hour.
Approximation
An approximate numerical result would be: twenty-one feet per second is about fourteen point three two miles per hour, or alternatively, a mile per hour is about zero point zero seven times twenty-one feet per second.
Footnotes
[1] 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.