Answer
$5.33$mi/h
Work Step by Step
As per the given problem, we have:
$F=kAs^2$
Here, $k$ is defined as constant of proportionality
Plug the given values in the above expression, we get
$220=k(40)(5)^2$
$\implies k=\dfrac{220}{(40)(25)}=0.22$
When $F=175 lb$ ; $A=28 ft^2$ and $k=0.22$
The, we have $175=(0.22) (28)(s^2)$
$s^2=\sqrt {28.41}=5.33$mi/h