# Which Water Tank Piston Requires More Force?

• morfzcspls
In summary: Assume two 4 ft diameter by 25 ft tall water tanks, both equally filled to 23 ft. Both tanks have chambers of the same diameter as the tank attached below them. Each chamber has a piston and has 2 ft of water above their pistons. Both chambers have a 4 inch diameter hose going from their chambers and into the tanks. On one of them, the other end of the hose is penetrates the tank at 3 feet above the chamber. On the other the hose penetrates the tank at 22 ft above the chamber. In summary, the pressure head at a point inside a body of liquid is given by
morfzcspls
It may be a simple question to you but I need help understanding head pressure and I need to set things up to ask it.

Assume two 4 ft diameter by 25 ft tall water tanks, both are equally filled to 23 ft. Both tanks have chambers of the same diameter as the tank attached below them. Each chamber has a piston and has 2 ft of water above their pistons. Both chambers have a 4 inch diameter hose going from their chambers and into the tanks. On one of them, the other end of the hose penetrates the tank at 3 feet above the chamber. On the other the hose penetrates the tank at 22 ft above the chamber.

My question is, which piston will require more force or is there any difference. I would also appreciate any explanation that you want to include.

Last edited:
morfzcspls said:
Assume two 4 ft diameter by 25 ft tall water tanks, both equally filled to 23 ft. Both tanks have chambers of the same diameter as the tank attached below them. Each chamber a piston and has 2 ft of water above their pistons. Both chambers have a 4 inch diameter hose going from their chambers and into the tanks. On one of them, the other end of the hose is penetrates the tank at 3 feet above the chamber. On the other the hose is penetrates the tank at 22 ft above the chamber.
Ahh.. Can you show a simple diagram?

1 person
The pressure head depends on the density and elevation of liquid (or gas) above a given point by virtue of ρgΔh, where ρ is the mean fluid density, g is the acceleration of gravity, and Δh is the height of the fluid above the point of interest. The higher the column of water, the greater the pressure at the base or lowest point.

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

I have added a diagram called Undrstnd hd.png in hopes of clarifying this question.

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• Undrsnd hd.jpg
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Big fat blank. Please try again. Always use the 'preview' button to check how your material displays before you post.

Sorry for the problem with the picture I attached previously. I’m having an issue with the latest update of DraftSight not exporting DWG files. Several of the formerly possible file types (.png, .tif, .wmf, .emf) create the file but they are not visible. So it seems the attached JPEG is visible.

Thanks

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• phys question 01.jpg
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static pressure head at a point inside a body of liquid is given by ρgh , as Astronuc Stated, where h is the height of the column of water above the point of interest, think of it this way, if you have two paper cups filled to the brim with water, and you put a hole in each cup, one near the top, and one near the bottom, the water will flow out faster from the hole near the bottom , because the h is higher, ie the column of water is higher, hence the static pressure is higher. similarly, your piston with the hose near the base of the tank will experience greater pressure

## 1. What is head pressure?

Head pressure is a term used to describe the force exerted by a liquid or gas on a surface. It is typically measured in units of pressure, such as pounds per square inch (psi) or pascals (Pa).

## 2. How is head pressure calculated?

The formula for calculating head pressure is head pressure = density × gravitational acceleration × height. This formula takes into account the density of the liquid or gas, the strength of gravity, and the height of the liquid or gas column.

## 3. What factors affect head pressure?

The main factors that affect head pressure are the density and height of the liquid or gas, as well as the strength of gravity. Other factors that may play a role include temperature, surface tension, and the type of container or piping used.

## 4. What is the difference between static and dynamic head pressure?

Static head pressure refers to the pressure exerted by a liquid or gas that is not in motion. Dynamic head pressure, on the other hand, refers to the pressure exerted by a liquid or gas that is in motion, such as in a pump or a flowing pipe.

## 5. Why is understanding head pressure important in science?

Understanding head pressure is important in science because it plays a crucial role in many natural phenomena and industrial processes. It is used to measure and control the flow of liquids and gases, and is also important in fields such as fluid dynamics, hydrology, and meteorology.

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