Solving the Hardy Cross Problem

[foo9008]

Homework Statement

in this problem , we know that Q (flow rate ) has power of 2 , hf = k(Q^2) , shouldn't the hf = k(Q^2) has positive value ?

Homework Equations

The Attempt at a Solution

since (554)(-40^2) will become positive , same thing goes to hf / Q , when the hf = positive , the hf / Q will become hf / Q divided by Q(has negative value ) , so the hf / Q will have negative value , am i right ?

 

[foo9008]

why will (554)(-40^2) will become negative ?

 

[foo9008]

anybody can answer ?

 

[foo9008]

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