Find the gauge pressure (in psi) at the bottom of a freshwater swimming pool that is 17.4 ft deep.

Question

Find the gauge pressure (in psi) at the bottom of a freshwater swimming pool that is 17.4 ft deep.

Answer 1

Let

h = 17.4ft be the depth of the pool,

g = 9.8m/s² be gravitational acceleration,

r = 1g/cm³ be density of water.

The formula for pressure is

p = g r h

If you do not know why, please let me know.

First we calculate the part of the pressure at the bottom of the pool

due to water only, i.e. as if in vacuum.

Substituting actual numbers

p = 9.8m/s² x 1g/cm³ x 17.4ft

= 170.52 m g ft / (s² cm³)

= 170.52 100cm g ft / (s² cm³)

= 17052 g ft / (s² cm²)

= 17052 0.0022lb ft / (s² 0.39² in²)

= 246.64 lb ft / (s² in²)

= 246.64 psia

Now we remove the assumption of being in vacuum.

Assuming that the pool is at sea level, the pressure at the bottom of the pool

needs to be increased by atmospheric pressure.

But since you are supposed to calculate gauge pressure,

i.e., absolute pressure minus atmospheric pressure, the answer is

246.64 psig.