Question

What is the change in speed (in m/s) due to the Bernoulli effect as water goes into a 2.72 cm-diameter nozzle from a 8.69 cm-diameter fire hose while carrying a flow of 40.4 L/s?

Answer 1

Given : r2 = 1.36cm =0.0136 m

r1= 4.345cm= 0.0434 m ,

ρ 1000kg/m , g = 9.8m/s^2 , Q = 40.4 L/s

Plugging known information to get :

According to Continuity Equation,

Where:

Q = the volumetric flow rate

A = the cross sectional area of flow

V = the mean velocity  

Similarly,

Change in speed, v2 - v1 = 0.945 - 0.296 = 0.649 m/s => Δv= 0.65 m/s.