# pressure

1. ### How would you determine the volume of a cylinder with fixed volume given air pressure measurements over time and the ability to add more air.

In the system I am looking at: We have 3 scuba tanks of constant volumes V1, V2, V3. Any of these fixed volume tanks can be attached to an air compressor but this is done in secret so you do not know which tank was attached. The goal is to determine which of the fixed volume tank has been...
2. ### Changes of gas in a vessel with a tap

"A vessel of volume 2.0*10^-2 m^3 contains an ideal gas at a pressure of 1.50*10^5 Pa. A tap attached to the vessel is opened and the gas expands adiabatically until its pressure equals the atmospheric pressure of 1.01*10^5 Pa. The tap is then closed. The gas is allowed to return to its original...
3. ### How to determine air pressure?

In a restricted round tube what are the formulas for determining the pressure at the 3 designated areas? I would guess the far left section would be volume flow / restricting flow area. But I have no idea how to calculate after the main restriction. thanks for your help
4. ### Determining length of a tube with applied pressure

Hi folks, I have a question. Imagine i'm blowing air through a duct that is capped in one side. The tube is made of plastic and has a 14mm external radius and an internal readius of 10mm. If I apply a constant pressure of 16 bar, and it takes 30 seconds for the air to come out on the...
5. ### Python script to find drag force on a 2D object given differential pressure vectors

I am in need of a python program to calculate the drag force on a 2D object, given differential pressure acting on the object-- this will have to be calculated either manually or (hopefully) by the code. I have the exact location of each pressure vector via a .dat file, and would like to know...
6. ### Manipulating Sound Pressure Level

I've performed an experiment on guitar tone - ive used a fourier analysis to find the different frequency components. The idea of this is to find the sound pressure level of the consonant intervals present in a guitar tone and compare it to the SPL of the dissonant intervals. I have found the...
7. ### Pressure and Volume work

Hi everyone! This is my first post, so if you have tips on formatting please let me know. I am currently in a graduate level dynamics class and right now we are studying the first law of thermodynamics. The question that is giving me trouble is as follows: One day the atmosphere to...
8. ### Enthalpy formula

Hi guys, I am relatively new in Thermodynamics as I am an electrical engineer. Right now, I am looking for an exact enthalpy calculation formula. The Gas is N2 with Temperature 27C and Pressure 124.73 bar. From a paper the enthalphy is 288.28 kJ/kg. I also found the same answer from online...
9. ### Heliumgas pressure

Hello! I´d like some help solving this: In a 40l gasbottle there is helium in it´s normal state. With a constant temperature, 5 g of helium is added to the bottle. What is the new pressure?
10. ### Air plane pressure

So I'm flying on a jet and I have to swallow to reduce the pressure in my ears and a thought occurred to me. The jet is essentially a flying tube, sealed to maintain normal air pressure. But if it is sealed then how can the air pressure in the plane rise and fall? Thanks! -Dan
11. ### 2 blocks on top of each other exerting pressure on the ground

So the question is that there are 2 blocks on top of each other of different mass (M1 and M2) and different cross sectional areas (A1 and A2). They are lying on a smooth surface. What would be the pressure exerted by the blocks on the surface. a) (M1g/A1) +(M2g/A2) b) (M1g/A1) +(M2g/A1)...
12. ### Pressure difference of a room question

Hi, I am discussing with my friend how to get air to push out of a room like ventilation, but we are not sure how the pressure difference would work. If we had one side of the room sealed except for a hole where a fan would be blowing inward into the room, and then a door open on the...
13. ### Pressure in fluids question

A glass tube of cross-sectional area 1.0x10^-4 m^2 is partially filled with water. An oil with a density of 800kg/m^3 is slowly poured into the tube and floats on top of the water. The height of the oil above the water surface is 8cm. A) what is the change in pressure at a depth of 10 cm below...
14. ### Deriving an expression for Radiation Pressure from Black body function

https://photos.app.goo.gl/LWzgtJsCXs4zCCbc7 Hello, I am reading a book about Stellar Structure and Evolution and it takes an expression for the Black body function in terms of frequency and substitutes it into a 'Pressure Integral' to derive an expression for Radiation Pressure. It just...
15. ### the relationship between he boiling point and the vapour pressure

As I understand it, boiling takes place when the saturated vapour pressure equals to the atmospheric pressure. But, why does the vapour pressure need to be equal to the atmospheric pressure for water bubbles to form? According to this video, the atmospheric pressure is cancelled by the...
16. ### Calculating Mixture Critical Temperature and Pressure using Equation of State?

Hello Everyone, I am trying to calculate critical Temperature and Pressure of binary and ternary mixtures using equation of state. In particular, I am using Peng-Robinson Equation of State. I combined this with Van-der Waals critical criterion to get my result, but am way off experimental data...
17. ### pressure gradient in sphere

Have cylinder made from semipermeable material .There is positive pressure inside cylinder and negative pressure outside cylinder .How gradient of pressure will be changed if we convert from cylinder t o sphere? Thank you
18. ### Dust Collection - Static Pressure/CFM

So I am looking to create my own dust collection system for my wood working shop and I have found a blower that states to have high static pressure (16 inches) with 1700 CFM flow rate (XPower BR-292A Blower). I intend to use this blower to function as a dust collection system (i.e. heavy air...
19. ### Pressure - Tension Problem

A moored contact mine is an explosive tethered by a cable to the seafloor so that it sits just under the surface of the ocean, then explodes when a ship hits it. Imagine one is a 300 kg sphere with a radius of 0.600 m. If it is 4.00 m below the surface and the tether is low mass enough to be...
20. ### Water Cannon

EDIT B: Ok, this is what I did. I got rid of the rest to avoid confusion. The question: A cannon fires water such that it is a cylinder with a radius of 10 cm, and at an angle of 21.8 degrees. If the water lands 10 km away after 30 minutes, how much force is behind it, and how much pressure is...