The relative pressure at the bottom of the lake is given by
[tex]p_r = \rho g h[/tex]
where
[tex]\rho[/tex] is the water density
g is the gravitational acceleration
h is the depth at which the pressure is measured
At the bottom of the lake, h=27.8 m, so the relative pressure is
[tex]p_r = (1\cdot 10^3 kg/m^3)(9.81 m/s^2)(27.8 m)=2.72 \cdot 10^5 Pa[/tex]
To find the absolute pressure, we must add the atmospheric pressure, [tex]p_a[/tex], to this value:
[tex]p=p_r + p_a =2.72 \cdot 10^5 Pa + 1.013 \cdot 10^5 Pa =3.74 \cdot 10^5 Pa[/tex]
