# Determine Inside Diameter of Horizontal Pipe Constriction

• zetabug

## Homework Statement

The inside diameters of the larger portions of the horizontal pipe in Figure P9.40 are 2.80 cm. Water flows to the right at a rate of 2.00 10-4 m3/s. Determine the inside diameter of the constriction. Answer in (cm)

Here is the picture http://www.webassign.net/sf5/p9_40.gif" [Broken]

Could you guys please show me how to do this? Not just the answer I want to be able to grasp the concept. Thanks

## Homework Equations

I'd Assume
1/2pv^2 + pgy = 1/2 pv^2 + pgy
Has something to do with it, but I don't really know where to start.

## The Attempt at a Solution

Honestly I have no idea where to start. How does the info given relate to anything?
From the above equation I can get
1/2(1000)(2e-4)^2 + 1000 *9.8*.1?= 1/2 1000 (2e-4)^2? + 1000 *9.8* .25?

But this doesn't use a lot of the info. Any help would be appreciated.

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That equation is Bernoulli's equation, but you are missing a term for pressure. (Look it up!) Hint: The heights of the fluid in those vertical segments will tell you the pressure in the fluid at those points.