Question

A fish tank is a cube of size L × L × L, where L = 1 m, filled with water. Find

the force that the water pressure exerts on each of the side walls. The water pressure is p = ρgh, where
ρ = 1000 kg/m3
, g = 10 m/s2 and h is the depth.

Answer 1

At the bottom of the tank :

P = ρgH

P = (1000 kg/m³)(10 m/s²)(1 m)

P = 10000 N/m²

F = P • A

F = (10000 N/m²)(1 m²)

F = 10000 N

At the side of the tank :

Pav = ½ρgH

Pav = ½(1000 kg/m³)(10 m/s²)(1 m)

Pav = 5000 N/m²

F = P • A

F = (5000 N/m²)(1 m²)

F = 5000 N