Pressure difference in cylindrical water jet due to surface tension

[Amr719]

Homework Statement

By How much does the pressure in a cylinderical jet of water 4mm in diameter exceed the pressure of the surrounding atmosphere if the surface tension of water is 0.0718 N/M?

Homework Equations

The Attempt at a Solution

ΔP= σ/r=0.0718/2*10^-3 , This is the answer I have but I don't understand from where did he get this law . Isn't it supposed to be ΔP= 2σ/r instead ?[/B]

 

[Chestermiller]

Homework Statement

By How much does the pressure in a cylinderical jet of water 4mm in diameter exceed the pressure of the surrounding atmosphere if the surface tension of water is 0.0718 N/M?

Homework Equations

The Attempt at a Solution

ΔP= σ/r=0.0718/2*10^-3 , This is the answer I have but I don't understand from where did he get this law . Isn't it supposed to be ΔP= 2σ/r instead ?[/B]

On what basis do you feel it should be ΔP= 2σ/r?

Chet

 

[Amr719]

On what basis do you feel it should be ΔP= 2σ/r?

Chet

Sorry I was wrong , I understand it now