Question

A 6.0-cm-diameter horizontal pipe gradually narrows to 4.0 cm . When water flows through this pipe at a certain rate, the gauge pressure in these two sections is 33.0 kPa and 24.0 kPa , respectively. What is the volume rate of flow

Answer 1

from Bernoulli's Principle

P₁+(1/2)ρv₁²+ρgh₁=P₂+(1/2)ρv₂²+ρgh₂

Since the Pipe is horizontal, h₁=h₂

So, P₁+(1/2)ρv₁²=P₂+(1/2)ρv₂²

by using continuity equation

A₁⋅v₁=A₂⋅v₂
Where v₁ and v₂ are the velocities of water in the pipe.

Where A₁,A₂ are the cross sectional areas of the pipe