# Homework Help: Fluid Flow in a pipe

1. Dec 8, 2008

### hellblazer970

1. The problem statement, all variables and given/known data
Use the picture as a guide. P is the pressure in the pipe, and vi is the speed of a non-viscous incompressible fluid at locations i = 1,2,3,4,5.(For each statement select G-Greater than, L-Less than, or E-Equal to).

A) P1 is .... P4
B) v1 is .... 2v3
C) P4 is .... P5
D) P1 is .... P2
E) v4 is .... v5
F) P3 is .... P4
G) v1 is .... v2

2. Relevant equations
Bernoulli's Equation p + .5ρv^2 + ρgy
Continuity Equation: A2*v2=A2*v2

3. The attempt at a solution
A) P1 < P4 because P1 has a higher velocity, so pressure must decrease to compensate.
B) v1 > 2v3, if the diameter is doubled, the velocity is quadrupled as per continuity equation
C) P4 > P5 due to gravity (ρgy)
D) P1 > P2 due to gravity
E) v4 > v5, if v4 has more pressure, it has higher velocity
F) P3 < P4 due to gravity
G) v1 > v2, since P1 has a higher pressure it has a higher velocity

Is my reasoning correct, or do I have something backwards? I guess my main confusion is what effect gravity has on velocity of flow?

2. Dec 8, 2008

### Redbelly98

Staff Emeritus
Those all look good to me except for E and G.

What does the Continuity Equation say about the velocities?

3. Dec 14, 2008

### Stevebo

The answers to this question are as follows:

[Moderation Note: Complete solution removed. Hootenanny ]

stevebo

Last edited by a moderator: Dec 14, 2008
4. Dec 14, 2008

### Redbelly98

Staff Emeritus
Stevebo,

Please don't give direct answers to questions, that doesn't help people learn!