# Velocity in a pipe

1. ### fowler2k

6
I need to find the velocity within a pipe , I know the flow rate and diameter

Flow rate =0.01
Diameter =90mm

Am I correct in thinking to use V =Q/A

Where A is found using A=pi/4 x D^2

Using this I got A =0.0064m but somehow this does not seem quite right to me

Thanks

2. ### SteamKing

8,848
Staff Emeritus
Please include units for all quantities. How else can we tell what these numbers mean?

6
0.01m3 s-1

4. ### billy_joule

264
Yes, it's not quite right. Your answer is a length...you want an area.

5. ### fowler2k

6
Ah so it should be m^2 ?

6. ### JazzyJones

20
What are the units for your flow rate?

And also, Your equation for area includes the term D^2 which implies the diameter is being squared, so your answer for area should have the units mm^2.