What is the resulting force acting on water tank walls?

[halfaguava]

Hello,

I am trying to calculate the force exerted by the water pressure on the walls of two different water tanks. A cylindrical tank and a cuboid tank.

Are the following calculations correct? (It seems too easy!)

Using generic dimensions:

Cylindrical Tank: Height 1m, Diameter 1m
Cuboid Tank: 1m × 1m ×1m
Tanks are full: P = $$\rho$$gh= 1000 × 9.81 × 1 = 9810Pa

Internal Surface Area of Cylindrical Tank: $$\pi$$ × 1 × 1 = $$\pi$$m^3
Internal Surface Area of Cuboid Tank: 1 × 1 × 4sides = 4m^3

F = P × A

Force on Walls of Cylindrical Tank: 30kN
Force of Walls of Cuboid Tank: 39.24kN

Thanks in advance!

 

[cjl]

The problem with that is that the pressure on the sides isn't constant. The pressure on the sides is dependent on how much water is above that point.

 

[halfaguava]

In that case, I have calculated the total resulting force acting at a third of the way up the wall?