Calculate the water level in a pipe.

Click For Summary
SUMMARY

The discussion focuses on calculating the height of water in a closed iron pipe submerged in water, specifically a 2 m long pipe with a diameter of 3 inches. Using Boyle's Law, the relationship between pressure and volume is established, where the barometric pressure (100,000 Pa) serves as the initial pressure (p1). The hydrostatic pressure (p2) is derived from the water density (1 x 10^3 kg/m³) and gravitational acceleration, leading to the conclusion that the water level inside the pipe is approximately 5.2 cm.

PREREQUISITES
  • Understanding of Boyle's Law and its application in fluid mechanics
  • Basic knowledge of hydrostatic pressure calculations
  • Familiarity with unit conversions, particularly between metric and imperial systems
  • Concept of pressure equilibrium in fluid systems
NEXT STEPS
  • Study the principles of hydrostatics and fluid dynamics
  • Learn about Boyle's Law and its applications in real-world scenarios
  • Explore unit conversion techniques, especially for pressure and volume
  • Investigate the effects of temperature on gas laws and fluid behavior
USEFUL FOR

Students in physical chemistry, physics enthusiasts, and anyone preparing for exams involving fluid mechanics and pressure calculations.

collegekid
Messages
1
Reaction score
0
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
 
Physics news on Phys.org
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.
 
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
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 16 ·
Replies
16
Views
3K
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
5K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
10
Views
3K
  • · Replies 37 ·
2
Replies
37
Views
4K
  • · Replies 33 ·
2
Replies
33
Views
3K
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K