Air Definition and 1000 Threads

Hello, I would like to ask one question. What is the equation for the lift force of a rotating sphere when flying through the air: m = 0.25 g v = 130 m/s angular velocity = 105 rad/s radius = 3 mm air density = 1.2292 kg/m^3 air pressure = 101200 Pa air temperature = 15 °C = 288.15 K If anyone...

So in class today, we were talking about how if you fire a bullet aimed at a falling target and release the target and the bullet at the exact same time, they will surely collide. I asked if air resistance (since it’s not a constant force) wouldn’t affect the collision and my teacher didn’t have...

The dielectric strength of air (ie the maximum electric field that the material can withstand under ideal conditions without undergoing electrical breakdown and becoming electrically conductive) is 3 000 kV ( https://en.wikipedia.org/wiki/Dielectric_strength#Break_down_field_strength ). In...

Hi all I have a very quick question I'm trying to understand why a graph of Rebound height (m) vs Air Pressure (x axis) doesn't have a line of best fit which goes through the origin. I understand a basketball's bounce can be compared to the compression of a mass-spring system but then why...

How did you find PF?: Google l was asked how hot would our IT space get if we lost all air conditioning. The space is 20' x 15' x 10', We keep set point at 70 F and have 80 kW of load. Assuming this exists in a well insulate container with 20 racks of equipment. Doesn't have to be perfect but...

My current project involves constructing an air bubble system to protect stationary docks from ice heave or ice jacking during the winter months. Ice jacking is the vertical lift as ice expands. When this grabs piles supporting stationary docks, it can wreak havoc. I am mainly confused as to...

Which compressed air inlet to a ring (loop) pipeline would likely be best in terms of least turbulance and best flow (avoiding dead head)? Given: 1) The inlet has to be in the corner of the rectangular loop. 2) Air consumption will be constant and evenly distributed throughout the loop. 3)...

Hello, Something I’ve wondered about is those amazing air bubbles that are sometimes found in underwater caves. In particular, I was wondering how the depth of the water does or does not affects them. In my Figure 1 example, the water is 50 feet deep and air bubble in the cave has 3 feet of...

If one Googles for "laminar flow nozzle", one finds many interesting tutorials on creating a nozzle for a laminar water jet; a stream of water that remains coherent over a long distance without breaking up. These typically consist of a large-diameter tube with regions inside (like sponges and...

I am trying to determine the minimum piston weight/force that would be required to push the air from the air tank into the top of the supply tank, filling up the supply tank and purging the discarded water thru the outlet supply pipe. We can assume no friction loss and sufficient air in the air...

The air is full of nitrogen and oxygen but can this somehow be reacted together to make N2O without any other chemicals involved (other than as a catalyst or other non consumable role)?

In winter I heat my workshop with a radiant heater and an oil heater. Easy to know how much heat is entering the room. But in spring and summer I don't use those; I blow hot air from the ceiling cavity into the room, and I was wondering how I would estimate the heating power and the formula to...

I am making my own humidifier, the store bought heat based humidifiers seem to all die very fast from how hard the water is where I live. I am pumping air from an aquarium air pump (A) into a sealed gallon of water (B) through an airstone (C) so that bubbles (D) rise through water and hydrated...

maybe the temperature need to be changed from Celsius to Kelvin

Apparently, it's possible to cool surfaces below ambient air temperature by passive (no input of energy required) radiative cooling to harvest water from the atmosphere: https://www.science.org/doi/10.1126/sciadv.abf3978 There's also a Nature paper about this effect, but behind a paywall...

I am not sure how to even start this problem.

In the first figure, air goes forward and the can goes backward. My question is why does the air exert the pressure gradient force on the can. Can I have a hint for why the can doesn't move when air is being sucked in in the second photo.

If you had a tube a couple of miles long filled with very compressed air, say 6,000 PSI, would an object you dropped in it fall very slowly? Even a heavy object like an anvil, how long would it take to drop?

Hi! I am really stuck on the concept, wouldn't we not have enough variables? I tried equation the equation for the y of the object to the slope of the hill, but I am missing several variables. Any help is greatly appreciated :) thanks!

I've recently started using a CPAP machine, which filters air and pumps it through a water chamber to humidify it. After a night of sleeping with it, I take it off in the morning and, once I breathe normal air, it has a very strong and distinctive smell. To me, it smells like something metallic...

just a question, I mean, burning trash causes polluted air. then why can't we just filter the polluted air, separating the oxygen and other harmful gas and release only oxygen in the air? thus solving trash and polluted air at the same time.

I find myself in a space with air but no gravity. Say at ISS. Can I suck myself forward by sucking a straw? It reminds me somehow of Feynman's sprinkler. Also Mach looked at something like Feynman's sprinkler. Mach invented something alike. Four ex/inhalers of air, tubes, that are in/exhale air...

Solution 1: Force on air = Force on helicopter. ##F = \frac {dp} {dt} = v \frac {dm} {dt} = v^2 \rho A## ##P = Fv = \rho A v^3## Solution 2: Power from helicopter converted to rate of kinetic energy increase of air ##P = \frac {dE} {dt} = \frac {1} {2} v^2 \frac {dm} {dt} = \frac 1 2 \rho A...

If I connect a voltmeter with the positive terminal of a battery and leave the other wire hanging in the air, it won't measure anything since it's not a closed circuit. But if there was a way to measure the voltage between those two points, what would the voltage be? Or is this a meaningless...

Hi Guys, I am doing a Maxwell 3D&Icepak thermal simulation for a air coil. I want to get its temperature when loading 1.6A current. So I use Eddy Current type in Maxwell 3D and Temperature and Flow type in Icepak. Then I load 1.6A solid current and adaptive frequency of 800 MHz for the coil...

I'm not looking for someone to tell me the answer, just help steer me in the right direction. I feel like I need to find the air density or air velocity at entry to proceed, but I'm unsure any help and guidance is greatly apricated!

Suppose an isolated pipeline of known dimensions is being filled with air from the atmosphere (via a compressor) to a gauge pressure P1=2barg. A rupture disc at one end of the pipeline blows at this pressure, and the air inside the pressurized pipeline is released to the atmosphere. The rupture...

Hi, A Korean friend owns me money and plans to pay partial with his airconditioner. But the aircon model came from Korea. I just want to know if an air conditioner like Carrier of a specific model made in different countries have the same design, or do they have separate say Korean design, or...

I have been wondering about submarines for a while, and especially their ability to sink and rise on command. I understand that they do this through ballast tanks and replacing water with compressed air, which increases the buoyancy force and helps them rise. (I understand that my knowledge is...

Hi folks, very simple question, but have not been able to find an answer: Assume a vacuum pump pulls air through a pipe. Also assume that within the pipe run, there is an area with reduced cross section, creating a temporary increase in air velocity. Also assume the air is very moist, and is at...

I have an air condition that is 9.000 BTU and it states at the external unit that its Power is 1.2KW. However because I know that an air condition has inductive loads (motors) its power factor is not 1 so I am not sure 1.2KW is the real power consumed. I am thinking to calculate the power...

In all gas turbines air is first compressed using a compressor and then head added in a combustor and finally the hot pressurized air is expanded in nozzles to convert air contained energy to kinetic energy which can be harvested and transferred in the form of thrust or shaft rotation. My...

If we want to build domed cities on Mars ( which i think a much cheaper option than O Neill cylinders) we need lots of local material. As far as i know oxygen and water arent scarce much of theese materials didnt escape but became peroxides and ice in the regolith. However are there enough...

Hi everyone After I've cooked beans in a pressure cooker, I put the cooker (with beans inside) into a sink full of water to help it cool down. After a while, the water heats up. At this point, would the cooker cool faster if I left it in the sink or if I took it out again? I'm guessing it...

Hi I purchased a vacuum container on amazon, the type with the glass and rubber lid. I didn't want to spend a bunch of money to buy an electronic air vacuum so I just bought a hand pump instead. Only problem is the hand pump doesn't seem to create a vacuum, even though I verified the hand pump...

Ideas on moving hot air from houseboat to enhance natural flow with additional solar 12v fans. 50 foot pontoon houseboat mobile home style cabin in desert southwest. Boat has windows but takes hours to cool down in evening when outside temp is cooler. working to isolate why cabin stores so much...

Hi, If you have dirty window type airconditioner in a room and it hasn't been washed or cleaned for say 3 years since installed, can the dusts, molds, etc. inside the airconditioner got into your lungs and become sort of like streaky infiltrates? Or does it simply circulate the existing dusts...

mentor note: moved from ME forum hence no HW template. Summary:: I am stuck into this problem for almost a week now. I think I solved it, but it seems something is wrong. Can someone point me, what is wrong here. It'll be so much helpful. I am stuck into this problem for almost a week now. I...

Hi there. I would like to start saying that I am not an engineer or scientist, and that my knowledge about vacuum and vacuum systems, in general, is limited, and I would like to apologize in advance if I am not describing the problem accurately. The application I am posing this question about...

All the popular definitions of 'air pressure' that I have seen say: "air pressure is the weight of the column of air above you". This seems misleading to me. - -...

Volume of hot air ballon V=((4/3 pi R^3)/2) + (1/3 pi h (R^2 + r^2 + Rh) = 2956.24 m3 Balloon: R=9m h=15m r=1m m = 750 kg H = 5000m T = 373 K p1 = 101300 Pa p2 = 50650 Pa M(air) = 0.029 kg/mol F = mg - 7350 N

Is a high viscosity fluid(liquid), filled with air bubbles, more or less vicious than without air? Please provide the scientific principle behind that

Actually, the path can be precisely parabolic, but you will need quite an arm to get that result. More commonly, the path will be a section of an ellipse - one that terminate when it hits the ground. In general, it will be a segment of one of the conic sections.

Hello! I've come across this forum looking for an answer to an odd question related to energy production. I have no intention of creating infinite energy so don't worry. Imagine a very strong balloon with a cord wrapped tightly around it. The balloon expands pulling the cord which spins a...

I'm trying to solve this problem using an rtz coordinate system, and Newtons second law. I know that mar = (m(v)2)/r. I'm failing to understand how mg and the drag force affects the solution and how I would set it up. I know if it was at the bottom of the circle that mg would be added to the...

If evaporative cooling (Such as sweating) is due to the escape of the hottest molecules into the air thereby lowering the total average temperature of the water then that means that that hot water molecule has gone into the air and has made the air hotter, so then how does evaporative cooling...

With regard to relativity of simultaneity and the "block" universe and reflecting on the notion of skewed time slices associated with frames moving relative to each other, one observer sees one event a distance away (parallel to the direction of motion) occurring before another event a distance...

Typical box fan+air filter setups use axial consumer-grade fans designed for providing maximum air flow at low power consumption. These fans do not provide sufficient air flow at the high static pressure requirements typical of air filters. The air filters DIYers use are high Merv(e.g Merv 13)...

Hi, What can be done to avoid trupped bubble air at the top of a pressure vessel without upper hole during hydraulic testing? Also, once the bubble exist what can be done to release it? Thanks

Hi all, For an Isothermal compression process of air in a vessel with constant volume, I found the following expressions and and The first two give the same result, meanwhile the third gives another solution and I don't know why. For adiabatic compression I found these two expression which...