Velocity of a water jet given water pressure and diameter?

1. Oct 15, 2008

rufnrede

I need to determine the velocity of a water jet. For example, if a garden hose is 1/2" in diameter and we assume that the water pressure is 40psi, what would be the water velocity (in ft/s) as it exits the hose (assuming no nozzle)?

We know Pressure = force/area, but I want to know the velocity in feet/second, so I don't know what equation to use!

Since velocity has a time component, would we need to introduce another factor? Maybe estimate the gallons per minute? Is this known for a typical garden hose? Thank you in advance!
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Oct 15, 2008

mgb_phys

You can estimate flow speed from an orifice given just it's size, the presure and a factor that describes the shape.
Have you tried looking up orifice+flow in your textbook.

3. Jun 28, 2011

shortbits

.32 X GPM
_________ = Ft/Sec velocity
TFA (sq. in.)
http://www.uiweb.uidaho.edu/extension/lawn/Files/Garden_Hose.htm [Broken]

Last edited by a moderator: May 5, 2017
4. Jun 28, 2011

fizika_kz

Use the Newton's second law, considering a small dt amount of time.