Fluid Mechanics Viscosity Question 111
Question: Water is flowing through a tube of non-uniform cross-section ratio of the radius at entry and exit end of the pipe is 3 : 2. Then the ratio of velocities at entry and exit of liquid is [RPMT 2001]
Options:
A) 4 : 9
B) 9 : 4
C) 8 : 27
D) 1 : 1
Show Answer
Answer:
Correct Answer: A
Solution:
If velocities of water at entry and exit points are v1 and v2, then according to equation of continuity, $ A_{1}v_{1}=A_{2}v_{2} $ Þ $ \frac{v_{1}}{v_{2}}=\frac{A_{2}}{A_{1}}={{\left( \frac{r_{2}}{r_{1}} \right)}^{2}}={{\left( \frac{2}{3} \right)}^{2}}=\frac{4}{9} $
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