# Homework Help: Calculate the water level in a pipe.

1. Sep 29, 2005

### collegekid

This was a question on my last exam for physical chemistry. There were no examples in the book as to how to do this question and I think it pertains to physics. I would like to know how to do this in the event that it appears on the final.

"An iron pipe 2 m long and closed at one end is lowered vertically into water until the closed end is flush with the water surface. Calculate the height h of the water level in the pipe. Additional data: 25 degrees Celsius, diameter of pipe = 3 in, density of water is 1 x 10^3 kgm^-3, barometric pressure is 100,000 Pa = 10 hydrostatic head of water. Neglect the effect of water vapor pressure."

Thanks

2. Sep 29, 2005

### Tide

The level of the water inside the pipe will be such that the water pressure and air pressure at the interface are equal to each other.

3. Sep 19, 2011

### johnnykatz

Boyle's Law applies here: p1v1=p2v2

I am assuming barometric pressure is p1
p2 is calculated by hydrostatic pressure
p2=p1+density*g*height

v1 = pi*r2*h1 (convert units)
v2= p1v1/p2

h2=v1/(pi*r2)

I get 5.2 cm