Answer:
a) P = 9.58 psi for h=7.2 m
b) P=4.7 psi for h=5.94 m
Explanation:
Since the pressure Pon a static liquid level h is
P= p₀ + ρ*g*h
where p₀= initial pressure , ρ=density , g = gravity
then he variation of the liquid level Δh will produce a variation of pressure of
ΔP= ρ*g*Δh → ΔP/Δh = ρ*g = ( 15 psi - 3 psi) /( 8.6 m - 5.5 m) = 12/3.1 psi/m
if the liquid level is converted linearly
P = P₁ + ΔP/Δh*(h -h₁)
therefore choosing P₁ = 3 psi and h₁= 5.5 m , for h=7.2 m
P = 3 psi + 12/3.1 psi/m *(7.2 m -5.5 m) = 9.58 psi
then P = 9.58 psi for h=7.2 m
for P=4.7 psi
4.7 psi = 3 psi + 12/3.1 psi/m *(h -5.5 m)
h = (4.7 psi - 3 psi)/ (12/3.1 psi/m) + 5.5 m = 5.94 m
then P=4.7 psi for h=5.94 m