# What is Pressure force: Definition and 27 Discussions

Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled gage pressure) is the pressure relative to the ambient pressure.
Various units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the SI unit of pressure, the pascal (Pa), for example, is one newton per square metre (N/m2); similarly, the pound-force per square inch (psi) is the traditional unit of pressure in the imperial and U.S. customary systems. Pressure may also be expressed in terms of standard atmospheric pressure; the atmosphere (atm) is equal to this pressure, and the torr is defined as 1⁄760 of this. Manometric units such as the centimetre of water, millimetre of mercury, and inch of mercury are used to express pressures in terms of the height of column of a particular fluid in a manometer.

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1. ### Low Viscosity Oil, Tanks, Pressure Relief Valves and Check Valves

Hi Whoever, I have an idea for a system which would work for my food business but it doesn't exist. The system essentially relies on hydraulics, pressure relief valves and check valves for recirculation upon reached pressure. All tanks/pipes (The entire system) will be prefilled except for 1...

3. ### Pressure force on curved surfaces: vertical component

hi guys, i can't understand why they calculate F yin this way, the part of floor that is the vertical proyection has less water than the floor in the left so i tought Fy would be less, please can someone explain this concept to me?
4. ### Engineering Pressure Force on a partially submerged surface

Once I get the pressure, do I have to multiply times de area that is submerged (in this case it would be 25m^2), or do I take the whole area of the plate, including the part that is not submerged (in this case it would be 30 m^2) Thanks
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### Can a piezoelectric create dynamic pressure in oil fluid for energy harvesting?

Would it be possible to do a experimental setup where I create a dynamic pressure (10-500 Hz) of around 0.1-2 MPa, using a high force piezoelectric pushing on a piston on a Small volume of oil fluid. There is this paper, where the authors create a pressure wave of around 170 KPa using a...
6. ### Lateral pressure on tank walls

Hello, We are an importer of SCUBA diving equipment and are building a pool. I see multiple formulas and opinions, I'm hoping for a KISS answer. Although I don't think Width or length has anything to do with my question, we are building a deep shaft pool that will be 25'Wx35'Lx88'D. What is the...
7. ### Bernoullis & Pressure Gradient force

The more I learn about Bernoulli's the less I feel I understand it The problem statement If I had a ball (balloon) filled with fluid at pressure P being acted on by two opposing forces F+ and F- F+ being larger than F- there would be a net force accelerating the ball to the right but the...
8. ### Pressure force in water on truncated cone with air inside

Homework Statement Consider the truncated cone tank submerged in water: inside the truncated cone tank there is air. Evaluate the forces acting on the truncated cone tank. Homework EquationsThe Attempt at a Solution The forces are the following Boyuant force : $$F_b= \rho_w g V_{tank}$$...
9. ### Help with force & pressure on spine while bench pressing weights

Hey everyone. I've never been very good at math/science so I'm seeking a little help from this forum in hopes that there is someone out there who can provide me or guide me to an answer. What I'm trying to figure out is the difference in force or pressure exerted on the human spine for an...
10. ### Calculating Gauge Pressure on a Sphere

Homework Statement Homework Equations What is gauge pressure ? The Attempt at a Solution How to find gauge pressure ?
11. ### Calculating mass by pressure needed to move object

Homework Statement A cilinder is filled with 50mg of H2 gas. In the cilinder is a piston with a surface of 27cm The temperature of the gas equals 298K. The piston rises 2cm when the temperature rises 30 degrees. Calculate the mass of the piston Also given data: MH2=2.02g/mol Right answer...
12. ### What is the direction of pressure force and why is it confusing?

I am confused about the concept of pressure force. Let's say we have some pressure acting on a flat plate. Would the force associated with this pressure be oriented into or out of the plate? Intuition obviously tells me that the pressure force is acting into the plate, but the math appear to be...
13. ### Why is air pressure force not considered while weighing?

we know that air pressure on our Earth is 1 atm. Also 1 atm = 10^5 P Also we know Pressure(P) equation = P = F/A So, F = P*A So if small area(A) in which we are standing is also taken then pressure force is that area(A) times 10^5(Atmospheric pressure in Pascal) i.e 10^5*A So why don't we...
14. ### Pressure in a container placed on a reduced area?

Really simple question but it's been making me a little confused. Lets imagine we have a container (cubic with length of 1 meter) with a pressure of 1 Pascal and then an area inside the container of 1 mm^2 is chosen to measure the force on that area, what would the pressure be? 1 Pascal or...
15. ### Hydrostatics: What remains the same in a fluid?

I am looking into hydrostatics, but am now very confused about what has to remain constant in an incompressible fluid. I initially thought that pressure has to be the same all throughout the fluid, and that this is the reason why you can use water or oil when raising a car- you apply a small...
16. ### Is F in P=F/A an average or a sum of all microscopic forces?

Hello, I've read that the force F we use in the pressure formula P=F/A is an average of all microscopic forces exerted by the gas on the wall of the container over a period of time. Is it true? I thought it was a SUM rather than an average? I assume that in that definition the microscopic force...
17. ### Wind pressure force for complex profiles ?

How to calculate the force of wind pressure, for example for the surface tilted at 45 degrees? I need to find some serious work related to the wind pressure force calculated for different 3D shapes affected by wind from different angles. Can somebody recommend me the good names, keywords...
18. ### Pressure force on a control volume

Homework Statement http://postimg.org/image/4a8sv6umh/ Why do the pressure forces due to p1 and p2 act in the same direction? Homework EquationsThe Attempt at a Solution I thought that, given the direction of the flow, the pressure force on the bottom and top would act in opposite directions
19. ### Understanding Pressure Force Direction in Control Volumes

Homework Statement See attachment. The net pressure force on this control volume is P1*A - P2*A. My question concerns the direction signs. My thinking is this: The unit vector on the control volume naturally points outward (n hat). Since the pressure force PA is pushing TOWARDS the control...
20. ### Radiation Pressure Force on Earth

Homework Statement The intensity of sunlight reaching the Earth is 1360 \frac{W}{m^2}. a.) Assuming all sunlight is absorbed, what is the radiation pressure force on the earth? Give your answer in Newtons. F_r= b.) Give your answer as a fraction of the suns gravitational force on the earth...
21. ### Calculating the pressure force of a lever roller printing press

Hello Everyone. I need some advice in calculating the pressure of a roller printing machine. The machine is operated by a geared rotating lever which moves the impression roller across a print surface. I had thought it was a case of using the equation for rolling friction to work out the normal...
22. ### Hydrostatics - Why is the pressure force the same?

Homework Statement The Attempt at a Solution So for the cone there is the weight of the liquid (W), the upward force (F_y), and the pressure force acting on the bottom (F_v): F_v = W - F_y For the cylinder there is only the weight of the liquid and the pressure force acting on the...
23. ### Hydrostatic Pressure Force must be perpendicular

Hydrostatic Pressure Force "must" be perpendicular Hi, I'm taking AP Physics B and we started learning about fluids and pressure. My teacher told me that the pressure of a fluid acting in a a container only applies a perpendicular force to the sides, which doesn't make sense. If you 'zoomed...
24. ### Is Pressure Just Force Distributed Over an Area?

Hi (1) What does it mean to APPLY PRESSURE?? Don't we actually apply force that is interpreted into pressure by dividing it upon area of action? This question will clarify really the concept of Pascal's principle. (2) HOW CAN IT BE A SCALAR QUANTITY ALTHOUGH FORCE IS A VECTOR ONE? HOW can...
25. ### Finding Net Pressure force in a pipe

I have a pipe that has an inlet (x-direction) and outlet (y-direction) with water flowing through it. I want to find net pressure force in x-direction (at the inlet) I have momentum flux and areas of the inlet and outlet. How can I find the net pressure force acting on the inlet? I don't...
26. ### Net Force on Sides of Metal Box with Air at 1atm & 400K

A cubic metal box with sides of length 20cm contains air at pressure of 1atm and a temperature of 300K. The box is sealed so that the volume is constant and heated to 400K. What is the net force on each side of the box? thanks dudes.
27. ### Does Pressure Force Change with Container Volume in Water Filled Containers?

I've got a "dilemma" here about Pressure Force: " Containers with different volumes but with the same areas at the bottom are filled with water of equal mass. Will the Pressure Force vary according to containers?" First of all I guess Pressure Force must be equal to the Weight [W] of water...