Fluid Mechanics Viscosity Question 299
Question: If it takes 5 minutes to fill a 15 litre bucket from a water tap of diameter$ \frac{2}{\sqrt{\pi }}cm $ then the Reynold’s number for the flow is close to: (density of water$ =10^{3},kg/m^{3} $ and viscosity of water$ ={{10}^{-3}}Pa.s $ )
Options:
A) 1100
B) 11,000
C) 550
D) 5500
Show Answer
Answer:
Correct Answer: D
Solution:
[d] Given: Diameter of water tap$ =\frac{2}{\sqrt{\pi }}cm $ $ \therefore ,,,,,,Radius,,,,r=\frac{1}{\sqrt{\pi }}\times {{10}^{-2}}m,,,,\frac{dm}{dt}=\rho AV $ $ \frac{15}{5\times 60}=10^{3}\times \pi {{\left( \frac{1}{\sqrt{\pi }} \right)}^{2}}\times {{10}^{-4}}V\Rightarrow V=0.05m/s $ Reynold?s number, $ R_{e}=\frac{\rho Vr}{n} $ $ =\frac{10^{3}\times 0.5\times \frac{2}{\sqrt{\pi }}{{10}^{-2}}}{{{10}^{-3}}}\cong 5500 $
BETA
