Question

1–54 the absolute pressure in water at a depth of 9 m is read to be 185 kpa. Determine (a) the local atmospheric pressure, and (b) the absolute pressure at a depth of 5 m in a liquid whose specific gravity is 0.85 at the same location

Answer 1

solution:

$calculate the local atmospheric pressure\\

p_{abs}=p_{atm}+p_{gauge}\\

p_{abs}=p_{atm}+(p_{wgh})\\

185\times10^3=p_{atm}+(1000\times9.81\times9)\\

185000=p_{atm}+88290\\

p_{atm}=96710pa\\

=96.71kpa\\

b) calculate the density of the liquid\\

s=\frac{p_{l}}{p_{w}}\\

0.85=\frac{p_{l}}{1000}\\

p_{l}=850kg/m^3\\

calculate the absolute pressure\\

p_{abs}=p_{atm}+p_{gauge}\\

p_{abs}=p_{atm}+p_{lgh}

p_{abs}=[96710]+[850\times9.81\times5]\\

p_{abs}=138402.5pa

=138.4kpa$