Question

An open tank in a petroleum company lab contains a layer of oil on top of a layer of water. The water height is 5 times the oil height h. The oil has a specific gravity of 0.79. If the gage pressure at the bottom of the tank indicates 26.9 mm of mercury, determine the oil height h.

Answer 1

Answer:

Explanation:

Given

specific gravity of oil=0.79

height of oil column is h

height of water column is 5h

Gauge pressure at bottom is equivalent to $26.9\ mm$

$P_{gauge}=\rho_{Hg} gh_{Hg}$

$P_{gauge}=13.6\times 10^3\times 9.8\times 26.9\times 10^{-3}\ Pa$

Pressure due to oil and water  at bottom

$P=\rho _{oil}hg+\rho _{w}5hg$

$P=0.79\rho _whg+5\rho _whg=5.79\rho _{w}hg$

$P_{gauge}=P$

$13.6\times 10^3\times 9.8\times 26.9\times 10^{-3}=5.79\times 10^3\times 9.8\times h$

$h=63.18\ mm$