A cylindrical tank contains
pressurized nitrogen gas. The gage on the tank reads 88 kPa. A manometer is attached to the tank to verify its pressure. Determine the manometer reading in cm if the manometer
fluid is … 
a.) ρ_{mercury} = 13,600 kg/m^{3}, b.) ρ_{water} = 1000 kg/m^{3} 


Read: 
Remember that gage
pressure is the difference between the absolute pressure and atmospheric
pressure. 











Apply the Barometer
Equation with a known gage pressure to determine the manometer reading, h. 










Given: 
P_{gage} 
88 
kPa 







r_{w} 
1000 
kg/m^{3} 







r_{Hg} 
13600 
kg/m^{3} 
















Find: 
h 
??? 
m 
















Assumptions: 
1 The nitrogen and water
in the system are completely static. 




2 The densities of the nitrogen and water are uniform and constant. 




3 The acceleration of
gravity is: 


g 
9.8066 
m/s^{2} 







g_{C} 
1 
kgm/Ns^{2} 










Equations
/ Data / Solve: 


















Gage pressure is defined
by : 




Eqn 1 











The Manometer Equation tells us that : 




Eqn 2 











Combining Eqns 1 & 2 gives us : 




Eqn 3 











Now, we can solve Eqn 3 for h : 




Eqn 4 











Now, we can plug values
into Eqn 4 : 

a.) 
h 
0.660 
m 






b.) 
h 
8.974 
m 










Answers: 
a.) 
h 
0.66 
m 
















b.) 
h 
8.97 
m 


































