How Much Weight Is Needed to Increase PSI in a Water-Filled Cylinder?

[Kalagan]

Some numbers seem a little weird to me, I just want to get a second or third opinion on it.

Problem: How much Weight does it take to increase the PSI in a Cylinder filled with water by 10 PSI, 100 PSI, etc?

Assuming that there is a 1 ft tall Cylinder with 6 inches of water in it, with the AREA of the Cylinder floor being exactly 1 square inch; if you were to drop a Weighted Piston of exactly 10 lbs. on top of the Water, will that increase the PSI in the Cylinder by 10 PSI?

What I am really trying to figure out is, if there is a 110 ft tall by 20 ft wide Cylinder with 100 ft of water in it. How heavy will a Weighted Piston dropped on top of the water have to be to increase the PSI in the Cylinder 1 PSI, 10 PSI, 100 PSI? (Assuming that the Piston makes a perfect seal with the inner wall of the Cylinder and that Friction is nonexistent)

Are my calculations correct?

1) The area of the top of the water in Square Inches would be A = Pi x r squared, which would be A = 3.14 x (120 inches x 120 inches), so the Area of the top of the Water = 45,216 Square Inches
2) So to increase the PSI in the Cylinder by 1 PSI, you would have to drop a 45,216 lb Weighted Piston on top of the water?
3) To increase the PSI in the Cylinder by 10 PSI, you would have to drop a 452,160 lb Weighted Piston on top of the Water?

I think I am missing something, because those numbers seem TOO high for such a small increase in PSI. Can someone please help me here?

Thanks
Kalagan

 

[Dick]

You are thinking about the problem correctly. The weight is large because the area of the piston is large.

 

[m2003]

I would first like to clarify that weight and PSI are two different measurements. Weight is a measure of the force exerted by gravity on an object, while PSI (pounds per square inch) is a measure of pressure, which is defined as force per unit area. In order to increase the PSI in a cylinder, you would need to increase the force being applied to the water, not just the weight of the piston.

To calculate the force needed to increase the PSI in the cylinder, you would need to use the formula F = P x A, where F is the force, P is the pressure (in PSI), and A is the area (in square inches). So, for example, to increase the pressure in a 1 square inch cylinder by 10 PSI, you would need a force of 10 pounds.

In the scenario given, the area of the cylinder is much larger than 1 square inch, so the force needed to increase the PSI would also be larger. However, the weight of the piston alone would not be enough to increase the PSI by such a large amount. Other factors such as the speed and impact of the piston, as well as the properties of the water and cylinder walls, would also play a role.

Without more specific information and calculations, it is difficult to determine the exact weight needed to increase the PSI in the cylinder by a certain amount. It is always a good idea to double check calculations and seek multiple opinions to ensure accuracy. I would also recommend consulting with a qualified engineer for a more precise answer to this question.