Air Definition and 1000 Threads

For a construction I am building, I am stumbling on a rather basic physics question regarding pressure. Let's say I have a cubic bucket of 1m^3 that I place upside down on a water surface. I add a downward force (weight) of say 1000N submerging the bucket under water with the air captured...

Suppose we are driving on moon (I mean there is not air resistance) at a constant velocity. Suddenly the car goes on an icy land (the friction is zero). What happens? In other words, if we drive at constant velocity and there isn't air resistance, Is there any friction force between tires and...

molekule.com is the website I'm wondering if anyone has heard of these air purifiers. They are very costly compared to your standard Honeywell type that can be bought at a Big Box or Home Improvement store. The standard types are anywhere from $150-$400-ish. These Molekule purifiers are like...

Hey! This started very harmless... A friend and I were throwing stones in a lake. Mine didn't get very far, he was teasing me "What was the ideal angle again?". Of course, I know it should be 45°. I replied in jest: "That's because I'm considering air resistance!" Then we had a discussion what...

Densities of Normal Air is 1.225 kg/m3 at STP, whereas the density of Liquid Air is 870 kg/m3. That means liquid air is 710x denser that normal air. Then suppose, we compress normal air to more than 710 atmospheric pressure, then it could have a density more than that of liquid air. Is this...

Wondering why moisture ratio tables related to temperature and air only go up to roughly 50 C or so? is that temperature a "boundary" on the amount of water air can hold?

I have a friend and he complained that at school they are teaching that warm air rises. He said it's wrong. He said instead the cold air sinks. Is this true?

Hi, so I found this on another old "AP" High School Finals Exam. I think I may be super lost. Because the only way that I can think about is KE = 3/2kT. And then that the difference of the Kinetic Energy of the air Particles is the Q supplied by the heater inside the air dryer. So ## \frac...

Hi everyone! My name is Cristian and I would like to ask you for advice. I am trying to build a shredder for solid recycled plastics (particularly PP and PE) and I am seeking and motor to rotate the shaft of this device. Specifically, I require a motor with a 75 RPM speed and over 20 Nm torque...

I am working on an Air Blast Cannon for work and am having trouble finding the proper formulas to calibrate it. This Cannon needs to have a barrel with about a 4 inch bore. It will only be used to generate high speed air blasts, so it will not have a projectile. Are there any formulas or online...

Summary: I am looking to determine the velocity of a the gust of air normal to a falling object. Say if you to be standing next to an open frame building with a flat roof then take away all the columns and let the roof free fall. What kind of wind velocity would you experience. I am looking to...

I know heat is a form of energy, and that’s conserved, so usually an air conditioner will emit heat on one side, cooling on the other, probably increasing the overall heat in total. What’s not clear to me is if it always must do this, specifically if the air conditioner produces another form...

Are there any specific condintions for air to act as a screen? I just did my air wedge experiment yesterday and was wondering if we were to do it on a bigger scale, how would we do it?

I once was explained the answer to this question - something about both the air and the object being incompressible. However, for the life of me I cannot seem to reproduce the answer of why we ignore air pressure when doing basic calculations. If it matters, the particular system I'm interested...

There have been many notorious cases, both in recent history as well as in the more distant past, of meteors exploding in mid air, sometimes causing vast amounts of damage (or, in more minor cases, breaking windows etc). For example the so-called Tunguska Event is attributed to an air burst of a...

Hi, I know I've asked this before but I didn't manage to solve the problem before. To give context I'm trying to find the angle to hit a target with given coordinates from my current location in a particular game. (I'm modding the game) I can do it with zero problems when not including air...

Good morning all, How do you calculate the air pressure exerted on an average human of 1.9m2 I know the air pressure is 1.01kPa. Do I do, F = PA? 1.01kPa x 1.9? What are the calculations step by step? and what is it in bars? Does that mean it is 1.919 bar? Thank you,

Hi guys I am not certified engineer but I watched many videos to make home based mini air conditioners using Peltier module. So I decided to try this as experiment. My plan is if this small test project works well then I will proper mini a/c (for my small 10x10 feet office or at least for my...

How can we pump air into bicycle tire without opening the valve? I mean If valve (dunlop bicycle valve)is closed, then how pumped air going into the tire?

My plan is to use the compressor at work as a free ride to and from work. I want to install an air tank (a rated one, not an improvised one) onto a bicycle and then run an air motor to turn the wheel (with whatever gears etc needed to make it work). I will probably be using an air tool, such as...

I may be known on the EE side of PF as someone who hates waste and doesn’t like to throw away perfectly good machines; I like to resurrect faulty gear. This Dell printer was thrown away for want of a touch or two of solder, and works just fine. Do I really need to buy a whole new printer? This...

Yeah, not sure what to do

What would you change about air to make it have the same density at sea level but the atmosphere would only be a few miles high instead of a several hundred miles high? I am a high school physics teacher. As I ponder this possibility, my first thought is I could increase the strength of the...

Why air resistance has less force than gravitation force in free fall? If Egg is fall from a nest of tree, while falling, it has less magnitude of air resistance than gravitation force. Where net force is not equal to zero.

If we were to suppose the pokéball gets rid of the pokémons mass by expelling it as air, what would happen? Imagine we had a pokémon weighing 999.9kgs, being a perfect sphere and having a diameter of 10cms. (Cosmovum). If the Pokéball takes 1 sec to capture or to release a pokémon, and it...

some ideas so far: ozone generator, soap and water rinse, ammonia based cleaning solution, keep airing out maybe with a fan (but rather not risk any sparks and such either) Ideally I don’t want to have to try a dozen things, so I’ll see what ppl support the most. Thanks science ppl!

Initially the hot air balloon is stationary so... FB=Fg ρgV=mg m=1319.2...kg FB=Fg=12941N In the air... a=2d/t^2=0.933...m/s^2 Fnet=FB-Fg (1319-x)(0.93...)=12941-(1319-x)g x=114.6 kg but apparently this is wrong?...

Summary: The main idea of my graduation project is to convert the motorcycle engine to work on compressed air that come from a 180 L tank (10 bar compressed air inside the tank ) I have some problems to how calculate the required torque to move the cart . The main idea of my graduation project...

Hi, I posted a question a while ago which I have managed to do some more calculations for. I need a bit of help to see if they are correct. I am trying to obtain power and torque values at different rotational speeds of a single cylinder compressed air engine. The inlet pressure into the engine...

I have a problem that i cannot solve despite my best efforts. I do realize not all information here is relevant, but i still included it so you could get the full picture. Imagining we have a cylinder that is filled with dry air (normal air without water vapor) that has a fixed volume of 8,5...

does pressure in a compressed air system increase when going from a 2" air line to a 1" air line.

Hi, just thinking about a possible project and it may involve bolting aluminium plates together and putting a very small voltage across them. If I take two plates of aluminium, leave them to oxidise in air (we all know Al forms a surface layer) then is there a minimum voltage that will flow...

Hi,I am designing a compressed air engine for a project. A little stuck with calculations. I need to work out how long the engine will run at its top speed using a air pressure which is supplied from a compressed air tank.Compressed air pushed down a piston which is connected to a camshaft. As...

This seems like a simple thermodynamics question but I would like clarification. So the absolute critical temperature is 132.5 K (-221.17 F) and the absolute critical pressure is 3.77Mpa (546.7 psi). I understand that for temperatures above the critical point, a pure substance undergoes an...

Ok, we all know that density is mass/volume. So if air is 1.22kg/m3,If we increase pressure, volume will change, therefore density can change. So how does one calculate density of air at higher elevations. Where i currently live, at 4700ft above sea lvl, I am guessing air density is not...

Homework Statement https://imgur.com/lGas78X The solution to this question says 450Hz. However, when I attempted to compute the frequency using the wave equation and find the normal mode solutions, I get 750Hz 2. Homework Equations I suspect that the solution could be wrong, is that the...

I am trying to fill pipes with a volume of 556 cuft to 15,000 psi. I want to capture and re-use the heat generated from the compression process and re-use it. Is this amount of compression and heat exchanging possible with current technology

Hello everyone, I am wondering how to model ambient air around a thermoelectric module in COMSOL. I am fairly new to the software and am doing undergraduate research revolved around it. Any help or pertinent examples would be appreciated. I can send/post screenshots and or .mph files if it would...

<Moderator's note: Moved from a homework forum.> Dear team, I wish to use CO2 to de-air a device by exploiting the physical properties of CO2 as a heavier, more dense gas to air and therefore displace air in a very thin tube that has a nozzle at the end where both air and CO2 can escape. I wish...

Homework Statement Serway Physics - P2.40 A glider of length 12.4 cm moves on an air track with constant acceleration (Fig P2.39). A time interval of 0.628 s elapses between the moment when its front end passes a fixed point A along the track and the moment when its back end passes this pont...

A marble rolls down an inclined plane with an angle of elevation of 5 degrees, roughly 4.9sin(5)m/s/s, and at normal pressure temperature NPT what would I need to add to S=1/2 at^2 to include the air resistance considering the marble is a sphere with a radius of 0.85cm and mass of 20g. The whole...

Trying to figure out how much air can (or would) flow through an air intake on a vehicle. I have a rectangular intake opening that is 13.52 square inches, the vehicle is traveling at 60 MPH for 1 hour. Obviously more air is being forced into the intake due to the speed but I can't sort out...

I have an interest in storing, for later use, energy from excess shaft power developed by a wind turbine. Currently I am assuming that the compressor is running in a steady fashion, continually drawing 300K, 1.0 atm. air into the compression chamber and compressing it to 20 atms. before...

I have a problem with my air conditioner fan not starting. As seen from the schematic below, when I test for voltage between the brown and black wires, I get 0 V (this is the problem). The indoor unit isn't sending the control signal to turn the fan on. The compressor powers on fine though. When...

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...

Homework Statement A baseball is hit into the air, nearly vertically, with a speed of 27 m/s. When it comes down, the ballplayer catches it in his glove. Air resistance (drag) is actually fairly important for a baseball in flight, but for now let’s assume it is negligible. (a) How high does...

Hi there, i have been working with a problem the past few days and have a hard time with some of the assumptions being made. The problem involves a piston in a tube which is connected to a vessel filled with air. The air behaves as an ideal gas to which the product PV^ζ is a constant. The...

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...

I have a 4 inch sphere with a 22 mm opening. Inside this sphere I will have 3 styrofoam balls 20mm diameter each and 3 styrofoam balls about 5 mm each. I need a wind source to blow wind into the ball through a tube approximately the diameter of a drinking straw, the wind being strong enough to...