 #1
 249
 1
Homework Statement
Determine the pressure of the water in pipe A shown in the figure (p2.56) if the gage pressure of the air in the tank is 2 psi.
I have attached the image
Homework Equations
The Attempt at a Solution
Figure P2.56
I drew a jumpline at 2ft above point A because everything below point A has the same density. From here I assigned P1 to account for the pressure above the jumpline in the tank and p2 to account for the pressure in the pipe adjacent to it.
P1 = P + ρ_{H2O}*3ft
P2 = P1 + ρ_{H2O}* 4 ft
P_{A} = P2 + ρ_{SG}*4ft
P_{A} = ρ_{SG}*4ft + ρ_{H2O}*4ft + P + ρ_{H2O}*3ft
γ_{H2O} = 62.4 lb/ft^{3} taken from textbook
SG = ρ_{fluid}/ρ_{[email protected]°}
ρ_{SG} = 0.9*1.940 slug/ft^{3}
P_{A} = 4ft(.9*1.940 slugs/ft^{3}) + 62.4 lb/ft^{3} + 2lb/in[SUP2[/SUP]*144in^{2}/1ft^{2} + 62.4lb/ft^{3}*3ft
P_{A} = 731.784 lb/ft^{2}
My answer should be 525 lb/ft^{2}
I'm not sure where I've gone wrong. I realize that I have slugs in my calculation witht he pressure of the fluid with the given SG but I'm not sure how to deal with them. Any suggestions would be appreciated.
Attachments

24.9 KB Views: 730