Fluid Mechanics Viscosity Question 240
Question: If pressure at half the depth of a lake is equal to 2/3 pressure at the bottom of the lake then what is the depth of the lake[RPET 2000]
Options:
A) 10m
B) 20m
C) 60m
D) 30m
Show Answer
Answer:
Correct Answer: B
Solution:
Pressure at half the depth $ =P_{0}+\frac{h}{2}dg $ Pressure at the bottom $ =P_{0}+h\rho g $ According to given condition $ P_{0}+\frac{h}{2}dg=\frac{2}{3}(P_{0}+hdg) $ Þ$ 3P_{0}+\frac{3h}{2}dg=2P_{0}+2hdg $ $ \Rightarrow h=\frac{2P_{0}}{dg}=\frac{2\times 10^{5}}{10^{3}\times 10}=20\ m $
BETA
