[SOLVED] Water flow in pipes

skier07

1. The problem statement, all variables and given/known data
Water is circulating through a closed system of pipes in a two floor apartment. On the first floor, the water has a gauge pressure of 3.4 x 10^5 Pa and a speed of 2.1 m/s. However, on the second floor, which is 4.0m higher, the speed of the water is 3.7m/s. The speeds are different because the pipe diameters are different. What is the gauge pressure of the water on the second floor?


2. Relevant equations
A1V1 = A2V2

P1 - .5(rho)(v1)^2 + (rho)gy1 = P2 + .5(rho)gy2

Efinal = Einitial
KEfinal + PE final = KEinitial + PE initial

Wnc = E1 - E2 = (.5mv1^2 + mgy1) - (.5mv2^2 + mgy2)




3. The attempt at a solution

Snazzy

Use Bernoulli's equation to solve it. You have what you need.

skier07

It doesn't matter that the Area changes?..also, I don't know what rho is? do I just use the standard rho of water?

Snazzy

They've already given you all the information you need. If they asked "find the area of the upper tube" then you would care about the fact that the two velocities are different.

skier07

what about rho though?

Snazzy

You know, or should know, the density of water.