Pressure Definition and 999 Threads

New member: Stem cell biologist by training, and many years since my last physics class. Imagine I take a water balloon and fill it completely with water. I then submerge the balloon in a beaker of water and place the glass inside a sealed chamber. What forces are applied to the water balloon...

Hi, I have a problem to understand one small thing. They say that air pressure per square cm at sea level is approximately 1 kg. So at 2 sq cm it will be 2 kg, at 3 sq cm it will be 3 kg etc. But... Here where I have a problem. The thing is that inside 2 square cm you can put 4 one square cm...

I've been searching and it seems I am not smart enough to find the solution for this... Let say I have a fully closed box made of concrete left in air. The pressure inside the box is 0.01atm. Since it is left in air, the air will come inside the box through concrete walls(since concrete is...

1. Problem Statement: The pressure in an gas tube of length L stretched along the x-axis is given by P(x, t) = Patm + P1(x, t) + P2(x, t) (1) where , P1(x, t) = 20 [P a] sin (−5.9 x − 1300 t ) P2(x, t) = 20 [P a] sin (5.9 x − 1300 t )One open end of the air tube is at x = 0m. By how much does...

Hello! I hope you are all doing well! I've been always intrigued by fluid mechanics and decided to try out a quick experiment with my water faucet. After using some equations I found online [1] [2], I plugged a hose to the faucet and let the water run. I filled a 1 quart bowl and recorded the...

my text box says that the pressure at point A is less than pressure at point B Are not they supposed to have same pressure as they are on the same horizontal plane ?

if we use a water manometer we get the pressure of the gas in manometer by using this forumla : Pgas = Patmosphere ± ρgh and if we use the a mercury manometer we use this formula instead : Pgas = Patmosphere ± h and here's my question : why cannot we use the first formula in both of them ...

Why the height of liquid is not affected by the radius of U-Shaped tube . ..my textbook says this and it does make sense because if increase the radius of u shaped tube the height of liquid should decrease as the liquids take shape of their container. Edit : I could not make the title longer...

Hello all. I have a question about gasses and pressure: Is there a way to calculate how strong a material making up a balloon has to be to withstand a given pressure difference between the inside and outside? In other words, if I have a balloon I need to fill to a pressure of 10atm inside vs...

Homework Statement see pic uploadedHomework Equations Pascal principal p = ρgh The Attempt at a Solution Pressure at C and D is the same . Pressure at A and B is the same ? I believe it is

In the derivation of finding pressure exerted by a gas using kinetic theory of gases I am not understanding why the time between two collisions is taken as the time for rate of change of momentum when a particle bounces back from the wall. please help me

Given that the gravitational field falls to zero at the centre of a large body (e.g. the earth), what happens to the pressure curve? (Assuming no effects due to high temperature.) Does it ease off too? What would the curve look like and what would the formula be?

I am trying to calculate pressure losses. I've attached an image to show what I mean. Starting out tank 1 is 92.8 litres at 155 psi and when the shutoff valve is open the volume goes from 92.8 to 192.8 and so I thought the pressure would drop by the same factor that the volume increased by so...

Homework Statement How to calculate time taken (rough approximation) for pressure equalization between two tanks. Both the tanks have same fluid (Air). Homework Equations Rough equilibrium pressure can be achieved by using equations Ptot = (P1V1+P2V2)/Vtot. Thought of using exponential...

I am trying to design a water vessel system that maintains it's water level as it is consumed. In item 1. It's a simple water barometer, where the height of water in the column can be supported by atmospheric pressure until 10.34. In item 2. There are two columns that are open to atmosphere...

Hello! I will try to formulate myself as clearly as possible, but english isn't my main language. I'm having trouble solving this problem that should be relatively easy to solve. Let's say we have a submerged pressure tank, constantly fed with air through a compressor, so it's maintained at a...

Hi, Pressure vessels have caps on top of them. These caps are secured with tri clamps and if you need to remove them you have to make sure that the tank's pressure is released. If the tank is under pressure (say 10psi) and an operator removes the cap (A is known), what is the speed of the cap?

Even today there are lot of misconception about how and WHY static pressure reduce above wing. 1)Faster air velocity cause low static pressure One involves holding a piece of paper horizontally so that it droops downward and then blowing over the top of it. As the demonstrator blows over...

Hi! This is my first post on here. I need to purchase an air cylinder, most likely hydraulic. The cylinder will have a forming die attached on the end and will be used to crimp two small stainless steel tubes together. The crimp will occur at an offset of .004 inches from each end of the tubes...

Homework Statement Two half with a fluid filled vessels are connected through two pipes in a closed system. The bottom pipe pumps the fluid from vessel 1 to vessel 2 at a rate of 300m³/h. The fluid pushes the air of vessel 2 through the top pipe into vessel 1. What is the pressure within the...

Homework Statement Consider a trough with triangular ends, as pictured below, where the tank is 10 feet long, the top is 5 feet wide, and the tank is 4 feet deep. Say that the trough is full to within 1 foot of the top with water of weight density 62.4 pounds/ft^3. How much force does the...

Hello, I am trying to understand the maths/physics/chemistry behind this situation. Here is the scenario. I have 8 grams of pressurized N2O in a cylinder at 60 bar/ 900 psi. If the temperature stays constant (let's say 50-70°C, or at a temperature where the N2O can stay as pressurized as...

Hello all, I am currently building a test bench that can input a high amount of flow, pressure and temperature into an Air Cycle machine. The inlet to the machine requirements are: Flow = 71 lbs/min P = 48 PSIa T = 235 degree F Diameter = 3 inches In order to produce these conditions, I have...

Homework Statement For the reaction below, the constant pressure heat of reaction is qp = −3256 kJ mol−1 at 25 °C. What is the constant volume heat of reaction, qV , at 25 °C? 16 CO(g) + 33 H2(g) ⟶ C16H34(l) + 16 H2O(l) Enter your answer in kJ mol−1, rounded to the nearest kilojoule...

Hello, I have a 8 gram cartridge of N2O meant for kitchens. Long story short from what I understand it has 10 cm cube of N2O inside. I also know it has 900 psi / 60 bar of pressure inside. The cylinder is exactly like this image. I am trying to find out how much time it would take if I...

Homework Statement [/B] Find the equation of state of a solid that has an isobaric expansion coefficient dV/dT = 2cT - bp and an isothermal pressure-volume coefficient dV/dp = -bT (Assume the solid has a volume Vo at zero temperature and pressure. Enter a mathematical equation. Use any variable...

Homework Statement I'm getting stuck with this one and in need of some direction! Obviously I'm not looking for a direct solution, but maybe a outline of what I should be doing? (I'll attach an image in a few minutes) <Image here incoming!> Known data: d2 = d1 / 2 F = thrust force (N) Pa = ρ...

I was reading about the Pendle Hill experiment by Henry Power and Richard Towneley showing the relationship between Volume and Pressure in gas that eventually became Boyle's Law. The higher they got the greater the volume became. My question is, was the gas measured in the barometer isolated...

Hi. Pascal's law states that static pressure in a confined incompressible fluid without gravity is the same everywhere. Is this law derivable from more fundamental laws? Some thoughts: Is Pascal's law part of the definition of the liquid state? If the liquid operates between two hydraulic...

Homework Statement forumlate if its growth/decay is exponential I have equation that i intergrated and found Pressure over volume = work done of pressure P = 3.2c^-1.4 f(v) = -8v^-0.4 i set limits of 10x10^-6 --> 100x10^-6 and 10x10^-6 --> 100x10^-6 but i increase both values by 20x10^-6 every...

I know the inlet pressure, temperature and density along with the massflow rate across the orifice and the orifice cross section. Is there a way for me to calculate the drop in pressure across the orifice?

Homework Statement Homework Equations Bernoulli equation. Continuity equation The Attempt at a Solution Area of pipe is constant, so v_a = v_b = v_c = v_d.[/B] Using point on water surface and point D. Point on water surface: z = 8, v = 0, P = 0 (P_atm) Point D: z = -2, P = 0 (P_atm) v =...

Homework Statement It is necessary to calculate the volume of the coin which has mass 25 kg and how does change its volume when it is necessary to calculate its volume at a depth of 5000m. Compare volume change by pressure with the volume change by pressure with the Volume change by...

Preface: Some people call the metering device on an air-conditioner the "expansion device". When I refer to the metering device in this post, metering device is synonymous with expansion device. ______________________________________________________________________________________ I'm a...

Is measuring pressure for a compressible fluid system angle dependent?For a compressible fluid, Bernoulli's Law gives us a relation between two points along a closed system. More specifically it gives us the relation between two cross sections belonging to two distinct points in the closed...

The Clausius-Clapeyron formula is given by \frac{d P}{d T} = \frac{L}{T \Delta V} where P and T are the pressure and temperature at the boiling point, respectively, and L is the latent heat per mole at the boiling point, and \Delta V is the change in the volume per mole between the gas and...

Homework Statement A vessel having a volume ##V## initially contains ##N## atoms of dilute (ideal) helium gas in thermal equilibrium with the surroundings at a temperature ##T##, with initial pressure ##P_{i} (T ,V ) = \frac{NRT}{V}## . After some time, a number of helium atoms adhere to the...

I am discussing with my friends to see which way is the best way to get the most stable branch outputs when one branch condition changed suddenly. There are three liquid flow branches, A, B and C, connected together with one pressure source, like this configuration: The Water Pump, #1...

Homework Statement A zeppelin of an ellipsoid shape (a=32m, b=c=a/3) iz filled with hydrogen. Pressure of the surrounding air is 100 000 Pa. Temperature of air and hydrogen is 20°C. The mass of an empty (not filled with hydrogen) zeppelin is 10 000 kg. What does the pressure of hydrogen inside...

My text (Ian Ford - Statistical physics) describes an ideal gas system in a piston being quasistatically compressed by a piston head of area A under external force f. It assumes the system has a uniform pressure p. All good so far. Then it says: "the force pA equals the applied external force f"...

Homework Statement An ideal gas has a molar mass of 40 g and a density of 1.2 kg m-3 at 80°C. What is its pressure at that temperature? Homework Equations PV=nRT R constant= 8.314 n= number of moles T= tempreture in kelvin density=Mass/ Volume The Attempt at a Solution i simply solved it like...

Consider a conventional U-tube with both the vertical tubes having the same uniform cross section area A and the horizontal tube of length L, connecting those tubes containing an ideal liquid. Now the free surfaces in both the vertical tubes will be at the same height and will have pressure...

Hello to all Can we consider the core of the Earth to be a superconductor ,for example Aragon national laboratory hinted for some thing like that https://www.anl.gov/article/nickel-for-thought-compound-shows-potential-for-hightemperature-superconductivity That been said , what test could...

Consider a fixed horizontal tube of uniform cross section with pressure being 1atm at one of it's end and 5atm at the other (former due to 'open to atmosphere' and latter due to force on a piston), then liquid would flow towards low pressure end. By equation of continuity all cross sections will...

Hello all, I'm new to this forum and I'm mucking about with some self-made physics conundrums, and I need some help! So, What I am aiming for is a roughly cylindrical vessel (it can, and I think probably has to, be tapered to achieve the effect) with the air being pumped out of one end, and a...

Assuming laminar viscous (meaning not frictionless) flow. Here is what I know about fluids flowing: You have a pressure difference between the two ends of the pipe. This causes a net force acting on the left side of the fluid in the pipe. Therefore, this incompressible fluid flows from left to...

Homework Statement The average pressure of the blood in a person’s arteries is 100 mmHg. What is the average pressure in an artery in the head of standing person 40 cm above the heart? (blood density= 1.05x103 kg/m3,Mercury density = 13.6x103 kg/m3 and g=10 m/s2) Homework EquationsThe...

I keep seeing a popular question asking about atmospheric pressure "crushing" us. The word "crush" throws me off. It is my understanding that air molecules create pressure due to collisions. In other words, the molecules exert pressure due to having kinetic energy - and the more molecules you...

Homework Statement [/B] dp/dh = -.13*p h in kilometers I should convert it into meters2. The attempt at a solution I thought it would be enough to multiply -0.13 by 1000. :( dp/dh = -130*p but it is wrong.

Hi everyone, I have been mulling over the relationship between pressure and boiling for some time, and I am still slightly confused. I shall attempt to provide an overview of my current understanding in the hope that I can get some corrections/clarification on my current conceptual...