# Pipe in network

1. Mar 25, 2016

### foo9008

1. The problem statement, all variables and given/known data
why the Q1 for AB is 5 ? for Ac is -5 , while for CB is -2 ? how to determine them ?
I could only see Qat A = 10.0 , Q at C = 3 , Q at B = 7
P/ s: the author take clockiwse direction to be positive , anticlockwise direction to be negative ...
2. Relevant equations

3. The attempt at a solution

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2. Mar 26, 2016

### foo9008

is the author wrong ?

3. Mar 27, 2016

### foo9008

can someone show Q1 for AB is 5 ? for Ac is -5 , while for CB is -2 ?

4. Apr 10, 2016

### foo9008

anybody can try to answer this ? i have been waiting for the explaination too long .

5. Apr 11, 2016

### haruspex

It's only a trial solution. Any values could have been used that add up correctly.

6. Apr 11, 2016

### foo9008

what do you mean by trial solution ? i'm confused.... how did the author get the Q= 5, -5 , and -2 based on 10 , 3 and 7 ?

7. Apr 11, 2016

### haruspex

I mean it is just an initial guess, consistent with the 10, 3 and 7. The method goes through an iteration to get closer to the actual solution. As an exercise, you could start with 6, -4 and -1 instead and check that you end up with the same final answer.

8. Apr 11, 2016

### foo9008

is there any rule to choose the 3 numbers for initial guess? e.g , if i choose the first number is 15 , will it affect the second and third number that i am choosing ? or it is just guessing ?