FInding distance from top of diving bell to lake surface

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Homework Help Overview

The discussion revolves around a problem involving a cylindrical diving bell submerged in a lake, where participants are tasked with determining the distance from the top of the bell to the lake surface based on the water level inside the bell and the pressures involved.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the relationship between the volumes of air and water in the bell, questioning the validity of the ratios used. There are attempts to apply principles such as Boyle's Law and hydrostatic pressure, while others express confusion about the definitions of variables and the implications of pressure changes with depth.

Discussion Status

The conversation is ongoing, with participants exploring various interpretations of the problem and questioning assumptions about pressure and volume changes. Some guidance has been offered regarding the application of pressure equations, but no consensus has been reached on the correct approach or solution.

Contextual Notes

Participants note the challenge of applying gas laws to a liquid scenario, highlighting the incompressibility of water and the need to clarify the definitions of pressure and volume in the context of the problem.

  • #31
Also I was focusing too much on the inside of the tube and missed that that interface sat at a certain height in the lake overall.

I solved it before with no idea about this. I guessed and missed all this thanks for the help!

One last thing. Is it corret to say that the pressures at that interface are the same?
 
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  • #32
Moose100 said:
Is it corret to say that the pressures at that interface are the same?
Yes. Action and reaction, equal and opposite.
 
  • #33
Ok. So the air portion in the tube has a uniform pressure correct? While the fluid portion varies with depth?

This is why there is a partition. The Gas exerts the same pressure on the liquid as it does on the gas.
 
  • #34
Moose100 said:
Ok. So the air portion in the tube has a uniform pressure correct? While the fluid portion varies with depth?

This is why there is a partition. The Gas exerts the same pressure on the liquid as it does on the gas.
Yes. Strictly speaking, the pressure also varies with depth in the air, but the density of air is so low that you can ignore that over a height of a few metres.
 
  • #35
RIght because gravity does affect it but so much that it's negligible so. You can use pascual on gases so to speak but the affect or calulation would be super small..

I guess another way to look at it is that the gas has to be equal because it stops the water from moving(equal and opposite).