$4-21$E$.$ A directional control valve with an effective area of $0\mathrm{.}5i{n}^2$ provides a pressure drop

of $40$ psi at $60$ gpm $.$ If the fluid has a specific gravity of $0\mathrm{.}90,$ what are the flow coef$-$

ficient and $K$ factor for the valve?

The answer is $0\mathrm{.}473$ and $4\mathrm{.}43$