Air pressure Definition and 207 Threads

Pressure is defined like FORCE/SURFACE [Pa] so the outside pressure close to the Earth is atmosphere pressure (101 325 Pa) defined by the mass of air/surface.Why is the same pressure in my house? There isn't much air like in outside...Thanks for the potential answer an sorry for the bad english.

Hi, We learned that, air pressure in a closed container is actually related to the quantity and speed of gas molecules hitting on the container's walls. So kinetic energy of the molecules determines the air pressure. However, isn't the fact that air pressure decreases when the speed of...

Well, I'm trying to grasp the concepts behind the following problem : "A guy puts some air in a vassel, the air's temperature was t0 the vessel's basis area is 50 cm³ and the height is 20. Afterwards the vassel was set onto a container full of water at 300k (Similar to Torricelli...

Is the air pressure near an object making lots of noise (e.g. engine, speaker) higher than the air around it?

HI In Jet Engine, i want to know that the compressed air prssure changes before it enters into the combustion chamber from the compressor in various altitude and velocity or it is consatnt for altitude and velocity?

i was just thinking recently and thought that since drag is caused by a body colliding with air particles. It would be logical to think that when there is relatively lower air pressure, there would be less particles to run into, therefore less drag, and therefore you would run faster.

How much air pressure could a human survive in?

Homework Statement The air temperature and pressure in a laboratory are 22°C and 1.3 atm. A 2.05 L container is open to the air. The container is then sealed and placed in a bath of boiling water. After reaching thermal equilibrium, the container is open. How many moles of air escape...

Hi, I understand the thumb rule that " the pressure exerted by ten metres depth of water is approximately equal to one atmosphere". Is it applicable for pneumatic systems too ?? that with 10 m head difference in air pressure lines there would be 1 bar difference in pressure between the ends...

Hi, I hope you can help me please. I have an AA battery here that has a weight of 10 grams, I would like to know what 10 grams of weight is equals to in air pressure like mill bar or PSI, can you help please? Many thanks in advance Christopher

Homework Statement In a tornado, the pressure can be 15 percent below normal atmospheric pressure. Suppose that a tornado occurred outside a door that is 195 cm high and 91 cm wide. What net force would be exerted on the door by a sudden 15 percent drop in normal atmospheric pressure? In what...

Homework Statement in a cylinder there is 30g of air which starts with a volume of 3L and pressure 0.1MPa. What will be the density of the air when the piston of the cylinder compresses the air to 0.5MPa ? Homework Equations The Attempt at a Solution

Weight of Air Pressure... How much air pressure (in lbs) is being exerted on the front of a vehicle per MPH it travels? I know all vehicles are shaped differently, so we'll focus on the license plate. -No headwind, tailwind or any other wind -Vehicle is traveling at sea level -Vehicle is...

Hi Guys, First time posting, sorry if this isn't the right place to post this kind of question. A personal project involving air pressure and propulsion has lead me to a question I hope somebody may know the answer to. Imagine hypothetically you have a turbine that has paddles with a...

Hi Folks- Is there a way to determine the air pressure caused by wind at a given mph on a human being? Thanks! MD

I think a ceiling fan would increase air pressure in a room, whilst an exhaust fan would decrease pressure if it was withdrawing air from the room. However with an exhaust fan, If the room was sealed off, wouldn't air tend to flow inwards through the exhaust fan as well in an attempt to equalize...

I would like the formula that describes the reduction in pressure that results when a constant flow (cfm) of compressed air travels from a 3" diameter pipe through a bell reducer that provides a smooth transition to a 1.5" diameter pipe. Also, in the same piping configuration as described...

Homework Statement "At the surface of a freshwater lake the air pressure is 1.1 atm. At what depth under water in the lake is the water pressure 4.5 atm?" Homework Equations I used the equation Pgauge = Dgh The Attempt at a Solution I converted my atm to Pascals-->...

How can I calculate the air-supply flow (q=cfm) needed to maintain, say, p=50 psi of pressure in a (quasi-rigid) cylinder with a Volume of V=30,000 cft, when this cylinder has an open gap (leak) 50 ft long (L=50 ft) and 1/8 inch wide (w=1/8 inch)? Is there a simple formula I can use to...

A gymnasium is 13.0 m high. By what percent is the air pressure at the floor greater than the air pressure at the ceiling?

Homework Statement The roof of a house has an area of 92.8 m^2. In a violent storm the air blows across the roof at a speed of 106.8 km/hr. Homework Equations Assuming that the air has a density of 1.25 kg/m^3, what pressure difference is created by the storm between the air outside...

Q: When a person inhales, air moves down the bronchus (windpipe) at 15 cm/s. The average flow speed doubles through a constriction in the bronchus. Assuming incrompressible flow, determine the pressure drop in the constriction. OK what confuses me is that I thought that if you decrease the...

I know about Bernoulli's principle and that a difference of pressure below and above a wing create lift, but I cannot find anywhere a formula or any information on how to find the amount of lift given the surface area of the wing and the difference in pressure as a percentage of atmospheric...

As title dipicts I'm wishing to understand the relationships between CFM and PSI in regards to Air Regulation. For example let's say I had a compressor tank with a compressor connected to it, to fill it to 200 PSI. I connect an X diameter Air line to an air regulator, and than have its...

I am trying to get some information to see if there exists a sub-system which can monitor air pressure (~200 psi) over a certain amount of time (less than 5 min.) and can output the readings so the information can be input real time or saved to a file which can later be input to Excel...

A small quantity of water is poured into a can, the water is brought to a boil. Then the can is sealed with a rubber stopper. As you watch, the can is slowly crushed with sounds of metal bending. Assuming the dimensions of the can are 0.24m x 0.16m x 0.10m and the inside of the can is in a...

Attached is an image of four simple systems, two are loudspeakers, two are air fans. My goal here is to examine if any of these "boxes" do anything to lower the peak amplitude of the energy in the system and which does it better and why. ................ Q1: Imagine the loudspeaker...

Hey all, I'm trying to do some math related to air pressure and temperature and i keep getting unreasonable answers. What i have is a cylinder (topless, diameter 3.5cm and height 10cm) with a piston placed inside it (diameter approx 3.5cm height 4 cm). Piston weights around .5kg. Piston is...

Air pressure and height... Ok, i have a hard time with the air pressure. I should do a calculation with the pressure and determine the height. I have a pressure sensor which i use for pitot-tube sensing and i have a static sensor of the same kind to measure static reference pressure. I can...

Homework Statement it told: 1. Water is forced out of a fire extinguisher by air pressure 2. the water level in the tank is 0.500 m. below the nozzle 3. find gauge air pressure in the tank (above atmosphere) for water jet to have speed of 30.0 m/s Homework Equations...

Homework Statement Estimate the air pressure at the center of a hurricane with wind speed of 300 km/h at the center. Answer in Pa Homework Equations P + 1/2 (density)(velocity)^2 density of air 1.29 kg/m^3 The Attempt at a Solution P + 0.5 (1.29 kg/m^3)(90000) Pressure = 58050...

THe question in "air pressure lesson". When I was studying about the air pressure, my teacher showed some examples about them, that is, the water in an upside down glass with covered by a card always do not fall in gravity. Then the question followed. I asked my teacher "Why do the water fall...

Im not exactly sure if this is the right section of the forums, but here is my question; is there any way to raise the air pressure inside a pipe for example, the only thing is, both ends lead into larger sections that open to the atmosphere. Air will be (for example) blown into the pipe from...

I've been wondering a couple things: 1. How much energy would it take to evacuate* a 1 cubic meter volume at sea level and some convenient temperature? 2. If the structure containing the vacuum weighed, say, 1kg, how high up would it go? *arbitrarily close to a vacuum to avoid getting into...

Nevermind, I think I figured out why I needed to set P2 = 0 in the first problem. Actually, what I needed to do was set P2 = 1 atm, and when I calculated force, I needed to use F = (P2 - P1) * A to get the right answer. So just ignore this...but here's the post anyway: For anyone who has...

The vertical surface of a reservoir dam that is in contact with the water is 170 m wide and 10 m high. The air pressure is one atmosphere. Find the magnitude of the total force acting on this surface in a completely filled reservoir. (Hint: The pressure varies linearly with depth, so you must...

Air pressure, P, decreases exponentially with the height, h, in meters above sea level: P = P0e-0.00012h where P0 is the air pressure at sea level. (a) At the top of Mount McKinley, height 6198 meters (about 20,330 feet), what is the air pressure, as a percent of the pressure at sea...

is there a formula which i can use to determine the the velocity of an object propelled by a gas under compression and a fluid? thanks Pavadrin

Any ideas how to start this problem (formulas or anything)? Just after its completion, the glass-walled skyscraper known as the John Hancock tower in Boston (see Figure P.64) was faced with an embarrassing problem: its windows kept falling out on windy days! The building soon became known as...

Suppose there exists a chamber of practical size (perhaps a prism with a square-base of 10 inch size, and 25 inch height). Now suppose I place an open jar into the chamber. If (and I say 'if' because i don't know how one would do this) a machine sucked all the air from the chamber, would...

. [Tipler5 15.P.049.] A sound wave in air produces a pressure variation given by the following formula, where p is in pascals, x is in meters, and t is in seconds. p(x,t) = 0.70 cos /2 (x - 330t) (a) Find the pressure amplitude of the sound wave. correct check mark Pa (b) Find the...

In a ten foot by 6 inch tall container filled with water were to have another container secured in it midway but had the pressure of air in it, (the bottom is open), if the smaller container has a siphon into it could you siphon in more water, or would the pressure that keeps the water from...

hi! i kinda grasp the concept of atmospheric pressure and how it affects everyday stuff... but I'm stuck with this one problem that i can't seem to understand. The experiment involves filling a cup with water. Then, a cardboard piece is placed completely over the opening of the cup and...

I have read that air pressure is about 100,000 pascalls which = 100,000 Newtons/m2 which is enough to accelarate a 1kg body with a surface area of 1m2 to 100,000 m/s in one second which is enough to accelarate a 100kg body with a surface area of 1m2 to 1000m/s in one second. Is this right...

I would like to review some principles, as well as pose some questions, to this highly intelligent community. As such, feedback of ideas, or comments, or even snotty remarks would be appreciated. Classical physics is built on Newton's laws. As such, Newton's laws always apply somewhere...

Ok. so say you have a fan that is moving air, at 1 atm, at about 10 m/s. what exactly happens to the pressure? does it change at all or...?

Doing a 7 th grade science project. Can a car run on compressed air? Ran a kids toy car using an 11 gal. air tank and 125 psi. how much farther would a car run with a 200 gal. tank and 4,000 psi. thanks.

Good afternoon Ladies & Gents, A question about the effect of air pressure on compressed air supply hoses. On the web site: http://www.engineeringtoolbox.com/air-altitude-pressure-25_462.html the absolute air pressure at 0 feet and 8000 feet, are given as 14.696 and 10.91 psi respectively...

is there any easy way, or relatively easy way, to calculate how much power is stored in a certain amount of air with a certain amount of pressure and flow? i know that's VERY vague, so let's say (random number's being chosen...) 30 psi at 100 cfm.

Hi I was wondering, I have a project in college where i am asked to make a sensor of some sort, i then proceded to make plans and decided on a pressure sensor, i have looked everywhere for an air pressure equation that i could use involving the density of air and the volume of the pvc pipe i...