# What volume flow rate will keep the pressures in the two horinontal pipes the same?

#### raywang5

1. Homework Statement
A liquid is flowing through a horizontal pipe whose radius is 0.02m. The pipe bends staight upward through a height of 10.0m and joins another horizontal pipe whose radius is 0.04m.

2. Homework Equations
what volume flow rate will keep the pressures in the two horinontal pipes the same?

3. The Attempt at a Solution
i tried to use p1+1/2xpxv1^2+pgh1=p2+1/2xpxv2^2+pgh2..
any idea?

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#### Spinnor

Gold Member
Re: what volume flow rate will keep the pressures in the two horinontal pipes the sam

1. Homework Statement
A liquid is flowing through a horizontal pipe whose radius is 0.02m. The pipe bends staight upward through a height of 10.0m and joins another horizontal pipe whose radius is 0.04m.

2. Homework Equations
what volume flow rate will keep the pressures in the two horinontal pipes the same?

3. The Attempt at a Solution
i tried to use p1+1/2xpxv1^2+pgh1=p2+1/2xpxv2^2+pgh2..
any idea?

I think you are dealing with the same formula I found in a Physics text:

p_1 + rho*(v_1)^2/2 +rho*g*y_1 =
p_2 + rho*(v_2)^2/2 +rho*g*y_2

Set y_1 = 0, y_2 = 10m, set p_1 = p_2 = p, and we know v_1 = v_2/4 (assuming incompressible flow)

and we are left with one equation and one unknown. Note the p's cancel along with the rho's.