The concept required to solve this problem is hydrostatic pressure. From the theory and assuming that the density of water on that planet is equal to that of the earth [tex](1000kg / m ^ 3)[/tex]we can mathematically define the pressure as
[tex]P = \rho g h[/tex]
Where,
[tex]\rho[/tex] = Density
h = Height
g = Gravitational acceleration
Rearranging the equation based on gravity
[tex]g = \frac{P_h}{\rho h}[/tex]
The mathematical problem gives us values such as:
[tex]P = 2.4 atm (\frac{101325Pa}{1atm}) = 243180Pa[/tex]
[tex]\rho = 1000kg/m^3[/tex]
[tex]h = 28.6m[/tex]
Replacing we have,
[tex]g = \frac{243180}{(1000)(28.6)}[/tex]
[tex]g = 8.5m/s^2[/tex]
Therefore the gravitational acceleration on the planet's surface is [tex]8.5m/s^2[/tex]
