Pressure Definition and 999 Threads

  1. P

    Is this kind of pressure chamber design possible?

    Hi! Given that the chamber is airtight and no air leakage occurs, is the design in the picture below possible? Can the pressure inside the chamber cause the button (black part at the top) to be "pushed"? https://imgur.com/a/wOSD30D Obviously the temperatures are over-exaggerated, but the...
  2. L

    Pressure while heated - half full or full container

    Hi I was in a discussion with some friends a couple of days ago. The discussion revolved the pressure raise in a liquid filled container. The question was, is the pressure behavior dependent on whether the container is filled with only water or filled 50/50 water/air. (The discussion started...
  3. T

    Do vacuum Ironing boards cause negative pressure in my Space

    Hey, I'm designing an HVAC system for a laundry building. I have vacuum equipment (Vacuum press and Vacuum Ironing boards ) in the space which have a vacuum outlet the is taken outside the building through individual ducts. When all machines are operational, 877 l/s of hot air and moisture would...
  4. ikihi

    Fluid dynamics: pressure in pipes

    So I've been discussing this problem with my plumber dad. I uploaded the picture. I'm wondering if the pressure would change in the red pipe since the diameter decreases to 4 cm. Assume the 1st 10 cm pipe is full with water. Question: If the home pressure is 517 kPa going through first pipe...
  5. M

    Pressure calculation, what am I doing wrong ?

    I have a 110 PSI pneumatic line. I have a 700 lbs linear force output. I have 1.230" outside diameter spring using 0.250" wire. My 110 PSI pneumatic line with cylinder is able to compress my 1.230" OD spring with 0.250" wire to 700 lbs linear force. My calculations reflect I should require...
  6. E

    Calculating airflow with pressure and diameter?

    Hi. Is there any way to calculate airflow out of a tube (into atmosphere) with only the pressure and cross sectional area of the tube?
  7. N

    A Phase transition under pressure?

    hello everybody does always phase undergoes transition when a pressure applied on a crystal ?even when the temperature is constant? and can pressure be increased without increasing temperature for a crystal? best regards Nawzad
  8. Mguidry43

    Needing to know the pressure in a water tank

    At work, we have a cylindrical tank that holds water. The tank is 5 feet round and about 6 feet long putting the highest part of the tank at about 6 feet off the ground. The tank holds 1000 gallons of water. There is a valve on the bottom that I am needing to test and I can’t seem to find a...
  9. Jesse Niekamp

    Bending Stress on a Protective Cover

    Homework Statement A 30kg pallet falls from a height of 2m onto a protective cover. The cover has an area of 269m² and an overall thickness of 10.9mm. a. What is the force/pressure on the cover? b. What is the bending stress on the cover? Homework Equations F=ma bending stress =...
  10. P

    I Chemical potential on a solid and its vapor pressure

    I have been reading the book "Nanostructures and Nanomaterials" by G. Cao and Y. Yang, and was intrigued by the following passage in page 33: "Assuming the vapor of solid phase obeys the ideal gas law, for the flat surface one can easily arrive at: μv − μ∞ = −kTlnP∞, where μv is the chemical...
  11. J

    Pressure and heights of a manometer -- Find the fluid flow rate

    Homework Statement Find the flow rate of water. The fluid in the manometer is mercury. ##d_{1},d_{2}## are the diameters in the figure Homework Equations Bernoulli, continuity equations The Attempt at a Solution We know that ##p_{1}=p_{1Top}+\rho_{water}gh_{2}##...
  12. DirtMonster

    Pressure & Gravity: Help for Vietnam Student

    My teacher say: Comparisons between the pressure of an object on the inclined plane and the gravity of the object But idk what is sin and cos means I need help THANKS from: vietnam
  13. Zahid Iftikhar

    Temp and Pressure measure of KE(average)

    Hi My question is related to interpretation of temperature and pressure in gases on the basis of kinetic molecular theory. According to it, both temperature and pressure are proportional to average translational kinetic energy of the gas molecules. Now in a situation where an ideal gas in...
  14. A

    Pressure gradient causes conservative force?

    Is the force that accelerates afluid betwen two points of different pressure conservative?
  15. B

    Effective Resistance (Fluid Mechanics)

    Imagine you have a vertical pressure head 2m tall with water flowing down to height 0m and emptying. Through this length we have 3 identical tubes of resistance R and length L. Assuming I know the volumetric flow rate(Q) as a function of height, how can I calculate the resistance of each tube...
  16. V

    Calculation of pressure variation due to fluid discharge

    Dear all, I have a headache and I need you help, with the following problem. I need to create excel sheet for the calculation (estimate) of the size of the orifice on the orifice plate that will produce a pressure reduction rate in pipeline at 0,5 bar per minute. It is not important to...
  17. S

    Why is Pressure Volume Work called P*delta V

    Why isn't it called deltaP *delta V work? Or deltaP*V work? Does the expression mean that P is constant while V changes and also what is an example of that? thanks for any help
  18. N

    Gas pressure regulator model in Simscape

    Hello, I want to develop a pressure regulator model in simscape. The model will be the springloaded direct acting system and the aim is to target outlet pressure, temperature and flow rate by giving input parameters as pressure, temperature, spring stiffness, length and preload, lever(it is...
  19. M

    Find the pressure put into a box by a hand-squeezed pump

    Homework Statement A spherical hand-held pump with a radius r is used to pump air into a cube with a length L. The pump and cube are connected together by rubber tubing. Express the pressure stored in the box as a function of the number of times the pump is fully squeezed. Imagine the...
  20. S

    Pressure Half-Life: 2L vs. 5L Containers

    Homework Statement A two litre sealed container is filled with air at atmospheric pressure. It is connected to a vacuum pump which can pump air at a flow rate that is proportional to the difference in pressure within the container to the pressure outside. This tells us that the pressure drops...
  21. Akash47

    Pressure at the bottom of a container containing two liquids

    Homework Statement (In the attachment)There is two layers of liquids in the container .The density of the upper layer of the container, ##ρ_1=800kg/m^3## and the density of the bottom layer of the container ,##ρ_2=13600kg/m^3## .What is the pressure at the bottom of the container? Homework...
  22. D

    Solving Consolidation Pressure: Half Layer of Clay?

    Homework Statement I don't understand why the pressure before the construction of foundation is given by (2.5)(16.5) + (0.5)(17.5-9.81) +(1.25)(16-9.81) only ?. Why the pressure is taken only to the half of the layer of clay only ? Homework EquationsThe Attempt at a Solution I think it's...
  23. A

    Calculating the velocity and pressure profiles across an axial fan

    Hi, This is my first post on the PhysicsFormus I am trying to design an inlet and outlet for an axial fan and calculate velocity and pressure profiles in the duct. See the sketch attached. The ultimate goal is to carry out a CFD study but I was wondering if there is an analytical solution for...
  24. Enzo777

    Automotive Finding the Peak Pressure of a Diesel Injection Pump

    I am trying to find peak pressure of a diesel engine injection pump.. It doesn't have to be exact but +/- 1000psi would be fine. The basic principle is the same as an engine. Piston goes up and covers a fill hole, once it is covered the only way it can flow fuel is through the injector, so...
  25. J

    MHB Pressure and Force - Fluid Dynamics

    HI All, I have been out of education a long time and am now back at college. One of my modules is Fluid Dynamics and I am beginning to struggle with the basics and could really use your help. I have attached a snip from one of the example questions below given to me by my lecturer. For part...
  26. Rain10399

    Finding the pressure of a gas in three identical balloons

    Homework Statement An adiabatic isolated system is formed of three identical balloons (of unknown volume). The balloons are joined by tubes of negligible volume. Each tube has a faucet/tap that is initially closed. The balloons have different quantities of the same ideal gas. After opening...
  27. CRuff

    Calculating kinetic energy turned into Pressure (Pascals) during an impact

    Hello, A silly question I'm sure, if a projectile moving at 13.59 m/s with a KE = 527.47 J hits an area of 3 cm^2, what is the force transfer to that area and the resultant pressure applied expressed in Pascals? Do I divide the KE by a volume instead of area to Pa?
  28. S

    Pressure in a 2" pipe branching into four 1" pipes

    Hello all, I am an Electronics Engineer, working in an R&D Organisation specializing in Electronics and Advanced Computing. My area of work is Control & Instrumentation related to Industrial Automation. I am trying to identify the a solenoid valve to be used on a 2" pipe. For this I need to...
  29. F

    How Does Pressure Affect Dissolved Oxygen in Water Systems?

    Hello Everyone, I've been trying to find an answer to this but am not getting anywhere. Any help would be greatly appreciated! I need to be able to calculate (or more likely estimate) the pressure drop I can expect when putting water under pressure if I know there is air in the system. For...
  30. H

    Is this calculation for radiation pressure correct?

    I was thinking about how much propulsion you could get out of a solar sail, so I just did a rough calculation: A solar sail 100m*100m in size (10'000m²), with 20grams of weight per m², an additional 100kg for probe and other stuff, so 300kg probe weight. Using the solar constant of 1400W/m²...
  31. jedishrfu

    Adm Grace Hopper: A Leader Under Pressure

    An article about Adm Grace Hopper http://americanhistory.si.edu/blog/grace-hopper
  32. D

    Effect of ambient pressure on Newton cooling (water)

    If I have a laboratory water bath (circulated for homogeneity in temp) that I will monitor over a period of time (probably 2 scenarios, an hour at most, and then at least 24 hours or longer), how do I quantify the effect of atmospheric pressure in our test lab. What I will do is use an...
  33. F

    Derivation of D'Alembert equation (for pressure waves)

    In my textbook there is an explanation of a derivation of D'Alembert equation for pressure waves. (##\frac{\partial^2 y}{\partial x^2}=\frac{\rho}{\beta}\frac{\partial^2 y}{\partial t^2}##) I put the picture (the only one I found on internet) but I'll call ##y_1 ,y_2## as ##\psi_1,\psi_2## and...
  34. L

    Why do bubbles of air in water move up?

    What I am confused about is why do bubbles of air in water move up. I understand why solids and liquids would move up in water if they are less dense. I get the idea that the deeper you go in water the more pressure there is because of the more water weighing down on the water and so there would...
  35. Navin

    Difference between Oxygen Tension and Partial Pressure

    Homework Statement What's the difference between Oxygen Tension And Partial Pressure Homework Equations ...uh...rules of grammar ? The Attempt at a Solution If I knew the solution I wouldn't be here now would I ? Here are a few links https://en.m.wikipedia.org/wiki/Blood_gas_tension...
  36. A

    Piezoelectric crystal and air pressure

    Will air pressure induce a voltage of a piezoelectric crystal or does it need to be mechanically compressed? My guess is that it would depend on the permeability of the crystal
  37. S

    I Compression of gases that liquefies

    For example we had a closed system with water at 298K, so it's pressure is 0.031atm. To it we add a gas, A such that we get 1atm of total pressure. That gas undergoes a phase transition at 1.5atm and 298K. So initially, the partial pressure of water is a little smaller than 0.031atm due to the...
  38. iamvksaini

    Flow Quality Impact on airfoil pressure distribution

    I have collected velocity data for a 3-D grid of test section of a low speed wind tunnel.I have tested airfoils for pressure distribution in the same test section for similar free stream conditions. How do I calculate the impact of flow quality in the test section on the test results of pressure...
  39. A

    Piezoelectric and air pressure

    I was just wondering if anyone could explain to me what would happen to a piezoelectric crystal on a closed circuit in a pressurised vessel?
  40. S

    Why does the partial pressure of H2O stay the same

    https://ibb.co/dxwnMe https://ibb.co/miNu1e In these slides they show the partial pressure of the H2O gas not changing when the enternal pressure on the entire gas is increased. Why is this the case? I know it condenses to maintain the same partial pressure, but couldn't the partial pressure of...
  41. N

    A manometer measures mechanical or thermodynamic pressure?

    Hi guys, I have two questions as follows, ofcourse they may seem too basic, I have read through certain texts (engineering) but I still haven't been able to actually physically understand, so asked here 1) Whats thermodynamic pressure w.r.t physical point of view? - for a gas from...
  42. J

    Nernst Equation with Pressure Differences

    I'm working with the Nernst equation with pressure differences right now: ## E = E_t + \frac{RT}{nF}ln ((P/P_0)^{\Delta \eta_G})## I'm assuming pure reactants here so, so I'm omitting the product terms: ##\frac{\Pi_{products} x_i ^{\nu_i}}{\Pi_{reactants} x_i ^{\nu_i}}## which would normally...
  43. J

    Finding the original pressure, thermodynamics

    Homework Statement Freon 12 is contained in a sealed glass container at 50°C. As it is cooled, vapor droplets arc noted condensing on the sidewalls at 20°C. Find the original pressure in the container. Homework EquationsThe Attempt at a Solution Looking at the Freon 12 table I subtracted the...
  44. N

    A Band Gap Vs Pressure: Proskite Compounds

    why band gap reduces when pressure increased for provskite compounds ? Nawzad
  45. T

    Pressure and temperature due to frictional or momentum input

    Hi, I have a hypothetical question: We have a fan which has no internal dissipation - electrical or mechanical. The fan is made to run in an adiabatically sealed room. The internal energy of the air in the room increases due to work input. This work input increases the temperature and...
  46. M

    Why can't we use the hydrostatic pressure gradient to do work?

    Is there any way to harness the hydrostatic pressure gradient to generate energy? The pressure at the surface of an ocean is atmospheric pressure.As we descend down the ocean, the pressure increases .After a point, the pressure will be very high.Why can't we use this pressure difference to do work?
  47. QuarkDecay

    How to Prove P+B²/8π in MHD Equilibrium?

    Homework Statement Prove that in an MHD equilibrium state in a pinch with flux and Bθ(r) and Bz(r), the equation for pressure is; d/dr(P + B2/8π) + Bθ2/4πr - ρ( u2θ/r)= 0 B is the total Magnetic field, uθ(r) the velocity of plasma, ρ= density, and solving in a (r,θ,z) system Homework...
  48. A

    Pressure and a Manual Valve's Effect on Pressure

    Think that there is 6 bar air (or water) feeding the system and there is a manuel valve before air comes to regulator. My question is that if I open the manuel valve half position do I change pressure (reduce it) or just reduce the flow ? For example, I have pneumatic valve whose working...
  49. B

    Model pressure loss vs time for air in a cylinder w/ hole

    Related to an engineering project I will be working on. The situation is that essentially I will have a closed cylinder (5.5 in x 26 in) with a small 15mm hole on the side (not on a circular face), which allows the air inside to be at equilibrium pressure/temperature with the outside. Then a...
  50. navneet9431

    Is P_atm=P_gas? Solving the Homework Problem

    Homework Statement See this question. Homework Equations Pressure=Height*Density*Gravity The Attempt at a Solution I think P_atm=P_gas. I think so because for the two liquids(oil and Hg) to be in equilibrium the net force on them should be zero. And,since they are not getting displaced...
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