There is a pipe whose diameter narrows smoothly from 10cm to 5.0cm. The pressure at where this pipe's diameter is 5cm is 50kPa. Given water's density of 1000kg/m^3, and a flow rate of 5.0L/s, what is the pressure at the point where the pipe's diameter is 10cm?(adsbygoogle = window.adsbygoogle || []).push({});

First the continuity equation:

Q=Av

0.005L/s=[pi(0.05/2)^2]v

v=2.546m/s

Then, Bernoulli's equation:

Substitute v1 for A2v2/A1

P1=50000+(.5)(1000)(2.564^2-[(pi*.05^2)(2.564)/(pi*.1^2)])

I left the potential energy out of the equation because it is negligible givien the number of significant figures we have. Even though I did the calculation with adding potential energy it is still wrong.

So I got 79993Pa. I know it is very wrong but I cannot check it since I don't have the answers. Any help please?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Pressure and flow rates

**Physics Forums | Science Articles, Homework Help, Discussion**