Question

Pressure in a water pipe on the ground floor of a building is 100,000 Pa. Calculate the pressure in the water pipe on the first floor at a height of 3 m. [Density of water = 1000 kgm⁻³ ; g = 10 ms⁻²]

Answer 1

Pressure of water at ground floor = P₁ = 1,00,000 Pa
Pressure of water at first floor = P₂ = ?
Height of first floor = h = 3 m
Density of water = ρ = 1000 kgm⁻³
Acceleration due to gravity = g = 10 ms⁻²
Difference in pressure of water at ground floor an first floor
= P₁ − P₂
Pressure of water due to height (h) = hρg
⇒ P₁ – P₂ = hρg
1,00,000 – P₂ = 3 × 1000 × 10 
P₂ = 1,00,000 − 30000
P₂ = 70000 Pa
∴ Pressure of water in a pipe at the first floor of a building is 70000 Pa.