Air Definition and 1000 Threads

  1. Some1WhoNeedsHelp

    Calculating the motion of air cylinder

    I am stuck at A, how do you calculate the motion of the air? I know ρ=m/V but what is the mass of the air, or I got that question wrong? Thanks
  2. D

    B Could Nuclear Powered Bulldozers Create a Habitable Cavity for a Mars Colony?

    Digging 8km under the lowest point on Mars will get us Mount Everest conditions for air pressure. I was thinking of two ways of doing said title: Nuclear powered bulldozers working around the clock to clear away dirt on a low point on Mars such as...
  3. V

    Why does less dense air rise and more dense air come down?

    My answer given below seems incomplete. Since warm air causes the air to expand in volume, so its density becomes less as compared to the colder air at the top of the room. After this, I generally find all books saying the less dense air rises and more dense air from top comes down and...
  4. daanisrael

    I How is the damping of sound (over distance) affected by air properties?

    Hey all, For my physics major I need to quantify the acoustic effect of sunfields. I'm trying to do this by measuring the sound level before and after a sunfield, and after that by measuring a comparable situation, only without a sunfield. By comparing the results of the two measurements I'll...
  5. Some1WhoNeedsHelp

    Need Help to Understand an Equation for Air Resistance

    I don't understand what the gamma letter in the equation is supposed to represent.
  6. B

    Calculating the speed air comes out of a fan

    Hi, I have a task where i have to calculate the speed of which the air is flowing out of a drones propeller fan. This is all i have been given: The mass of the drone m = 0.42kg, There are four propellers the lenght of each blade d = 0.21m, the air density is 1.3 kg/m3 and g=10 m/s^2y. And the...
  7. M

    Calculating turbine RPM in a pipe with known air velocity and diameter

    Hello, I am trying to calculate the turbine RPM for a turbine in a closed pipe. I know the air velocity and pipe diameter. Can this be done?
  8. Lotto

    B Can we use molecular speed of gas formula also for the air?

    Molecular speed of gas is generally $$v=\sqrt{\frac{3RT}{M}},$$where R is gas constant and M is molecular mass. Can we use this formula for the air as well, when the air is a mixture of different gasses?
  9. Gustavo Reis

    I Air Resistance: Exploring Hooke's Law

    Basically the air works like a spring, it always tries to get back to its resting state. And it's like Hooke's law, the more it deforms the more elastic potential energy it has. That's why the faster you are, the air resistance is greater. Thinking in this way, I imagine that in fluid mechanics...
  10. D

    B Air pressure generated by driving at 60mph

    If I place a 5' L x 12" W open box at front and a 1/8" hole at the back of the box and drove my car at 60 mph how much psi would I generate at the 1/8" hole?
  11. jhan

    B The Physics of blowing a puff of air

    If we noticed, when we released wind from our mouth with a constant velocity ,Why is the speed of the close part of our mouth is maximum speed and while gradually moving away is also gradually weakened until it is zero? How it can be resolved using in mathematical expression?
  12. G

    Reduce the pressure in an air reservoir

    TRANSITIONAL REGIME: ##\dot{V}=90\, \textrm{L}/\textrm{min}=0,0015\, \textrm{m}^3/\textrm{s}## $$\dfrac{d}{dt}\int_{VC}\rho\, dV=\dot{m}\rightarrow \dfrac{d}{dt}\rho V=\dot{m}\rightarrow $$ $$\boxed{\rho_{\textrm{air}}}\rightarrow pV=R'T\rightarrow \rho =\dfrac{p}{R'T}\rightarrow 287$$...
  13. A

    Air wedge - why is reflection from top of first slide ignored?

    My textbook derives the condition for bright and dark fringes on an air wedge by assuming that the reflected and refracted rays have a path difference of pi. Hence the conditions for bright and dark fringes end up being the opposite of what is expected. However I did not really understand the...
  14. A

    Air wedge interference pattern after being filled with water

    An air wedge is illuminated with light and an interference pattern is produced. What will happen to the interference pattern when the air wedge is filled with water? The answer given at the back of the book is that the fringe spacing of the interference pattern will increase, however my...
  15. S

    Distance travelled by a car considering only air friction?

    TL;DR Summary: Distance traveled by a car considering only air friction? How much distance would a 3-ton car travel if its initial speed was 17 km/h and we only take into account air's friction? (Assume that the car has an airfoil-like shape, so that the resistance against the air is very low)...
  16. agm

    Finding the Equivalence Ratio of Combustion (Methane + Air)

    I'd like to do some experiments with flames at different Equivalence Ratios - but I'm confused as to how I can find the Equivalence Ratio for different conditions. Wiki-article So the stoichiometric balance for Methane + Air is CH4 + 2(O2 + 3.76N2) -> CO2 + 2H2O + 7.52N2 Referencing equations...
  17. S

    I Transfer of electrical energy and transfer of air energy

    Is there a way to know what is the amount of energy a wire can transport and know what is the amount of energy transported by moving air at a certain psi.
  18. J

    I Air friction in rotating ring magnet

    As can be seen below we have 3 ring magnets. The middel one floats in between the other two. We want to know how to calculate the air friction of the middle ring magnet if this rotates.
  19. EddieP

    I Expelling warm air from voids - what is left afterwards?

    A cylinder contains a powder made up two substances - spherical grains of metal and spherical grains of plastic. In between the grains are voids, so that the cylinder is made up of 75% powder grains and 25% air. The cylinder is oriented vertically. It is sealed at the bottom and open at the top...
  20. EddieP

    Thermal expansion of air bubbles in plastic

    I am interested in the potential for air bubbles in a plastic structure to expand with heat, and put pressure on the plastic surrounding the air bubble. In this case the plastic structure is formed by melting a thermoplastic powder. In between the grains of powder are voids with air in them. As...
  21. M

    I Water bath and water vapor + air mixture in a closed system

    Hello, At my work I came up with the following question: Say we have a vacuum chamber. Inside the vacuum chamber we have at the bottom a water bath. The rest of the chamber is filled with a air and water vapor mixture. The whole system is placed in a room, is at room temperature and is in...
  22. K

    Using compressed air through a venturi pump to suck oil?

    Hello, was wondering if I could pass compressed air through a venturi pump to pull floating oil from a tank? If yes, how do I control the eventual mixing of oil with the air from the outlet end? The requirement is given to me by one of my clients who wants an easy, and low-cost solution to...
  23. L

    A Will air turbulence in flexible airduct causes water condensation?

    In a normal aircond system using flexible airduct, assume airflow with temperature & humidity conditions (Tdry=23°C; Tdew=13.4°C; RH=55% ) go through a bended flexible airduct where air turbulence is formed: 1. Can condensation happens at the bended flexible airduct due to air turbulence? 2...
  24. hxtasy

    Gerotor pump, will it work in a closed system without air?

    just hypothetical question, First off I am not very knowledgeable in pumps. Let's say you have a pump to pump fluid, i don't think the type matters, self priming as I understand it creates a vacuum with the air in the system to pull the fluid towards the gear pumps. I'm wondering what happens...
  25. D

    I need a small fan to push a lot of air because my bigger fan is too loud

    I remember a quick demonstration in high school of air like pushing more air thru a tube maybe 3-4in dia. than the little airbrush would push by itself? I think. I scaled that up at a weld shop with shop air and a 10in alum pipe that was like 3 feet long. I put a blow gun in the pipe and made a...
  26. Aethermimicus

    I What is the function of the air cavity inside drums?

    I'm trying to understand the function of the air cavity inside drums. I've read that 'The air cavity inside the drum will have a set of resonance frequencies determined by its shape and size. This will emphasize some frequencies at the expense of others.' Then what are the resonance...
  27. David Lewis

    A solar powered air conditioner

    1. In this system the sun boils Freon in a solar panel. 2. Freon vapor is sent to a turbine or piston motor. 3. Freon discharge from the motor is sent to condenser coils submerged underwater. 4. The cooled, low-pressure Freon is sent back to the solar panel inlet. 5. The Freon-powered motor...
  28. Spockishere

    How could you move a substantial amount of air to a certain direction?

    This may be a weird question, but i was just in the bathroom and had to think about it out of nowhere. I would appreciate any answers!
  29. jaumzaum

    I Why does hot air have low pressure? (wind formation)

    I was studying wind formation from the continent to the sea during day (direct circulation) and the explanation I found in almost all the textbooks was that: 1. In the continent during day the ground becomes hotter 2. The particles in the air increases their temperatures due to induction 3. When...
  30. S

    I Relative humidity question (cooling the air in a room)

    Hello everyone, I have a question about calculating Relative humidity. If I have a surrounding with 30 degrees Celsius and RH of 30%. I am cooling the surrounding with an air conditioner that works at 15 degrees Celcius. At the end of the process, the room reaches 25 degrees Celcius. In this...
  31. R

    B How does the density of air affect the note you hear?

    I'm making an instrument for a high school physics project and I was wondering how the density of air changes the perceived note and the explanation behind it. I've managed a few possible theories but none that I was fully confident in. I'll reference a video which inspired my idea, adding more...
  32. L

    Building a small hot air balloon

    Hypothetically how can someone build a small hot air balloon? I want to navigate a 360 camera to the air without needing a drone. Just a balloon, camera, and string to keep it from getting away. Maybe a remote fan to pull it down if string gets loose.
  33. G

    I Does high humidity air transfer sound better than dry air?

    Does high humidity air transfer sound better than dry air?
  34. E

    I Filling a rigid tire from a pressure regulated compressed air line

    This thought came to me while I was trying to fill my MTB bike tire a while ago as an exercise in laziness to not "check" the tire pressure with a separate gauge! Mostly, my mind just wanders... If I have some very large tank filled with compressed air at gauge pressure Ptank. The hose runs...
  35. Erwinux

    I Calculating the thermal coefficient between the insulated interior of a telescope instrument package and the cold ambient air outside

    I've built an insulated chamber to protect a sensitive instrument at freeze temperatures in the winter. The instrument is mounted on a telescope, so the heat inside the chamber will slowly dissipate in the ambient. A digital PID thermostat is used to keep the temperature at a safeguard level...
  36. Y

    Heat circle -- Calculating the air flow needed across a condenser

    Hi! I need to calculate what air flow needs to flow across the condenser so that the heat emitted from the condenser is directed to the air. dT=10÷15 [C] COP =~3 According to the manufacturer's data the fan airflow is 0.67 [m^3/sec] and i need to check if i can use it. thanks
  37. G

    Which fan placement offers the most airflow for cooling electronics?

    I have two identical fans to cool electronics within an enclosure. From the two drawings/options, which option offers the most airflow? Thank you.
  38. S

    Hospital Air Handler, Discharge Airflow vs. Static Pressure

    We have a new AHU installed for a Compounding Pharmacy. The unit has two return fans and two supply fans. They are installed in parallel and are powered by VFDs. In the event of one fan failing, the other fan is supposed to speed up to maintain static pressure in the clean environment. This...
  39. X

    Launching a Projectile with Air Resistance

    Mentor note: Moved from a technical forum section, so Homework Template is not present. Hello Physics Forums members, I am a student in AP Physics C and I was just working out the range of a projectile when air resistance is non-negligible. As of right now I'm going to use the linear model of...
  40. L

    Best fan placement for optimal air flow

    I'm building a fume extractor for my workbench. I would like to hear your thoughts on the best placement for a fan so I get the maximal suction/airflow. I made a sketch with the general dimensions. The fan could be either in the A position before the filter or in the B position after the...
  41. G

    Choosing a Flexible hose for outlet air pressure vessel

    Hi everyone, What should be the considerations to choose the proper hose (max working press) installed at outlet air pressure vessels (11 bar) for industrial purposes? Please remark source\link. Also, I've found a table which lists the max sys operating press for 4 different fluids (fuel, oil...
  42. r4g3r4hk

    B Does air resistance have a max value?

    I know that friction on a surface has a maximum value. When an object is pushed with a force greater than the maximum friction value, the object will move. But when a free-falling object falls from a height, does air resistance have a maximum value as well?
  43. M

    Does climate change affect air density at altitude (scale height)?

    Increases in global temperature change affect the tree line and presumably comfortable habitability via temperature, and average air pressure associated with weather patterns. That's not what I mean. I'm thinking a 1/50 increase in kelvin temperature might increase the scale height of Earth's...
  44. M

    I Can ground albedo near a highway refract noise upward?

    I live near some highways that are roughly "a couple of miles" away. On some blessed days they are inaudible, and on other days they roar with a low frequency sound that penetrates into every corner of the basement. (If frequency matters, it would be most preferable to refract sound at 20Hz...
  45. Arman777

    Ipad Air 5th Gen M1 Hardware properties compared to Intel i5-7200U CPU

    Hey all, I want to buy Ipad Air 5th Gen Tablet. Currently My computer has this specs: CPU(s): 4 On-line CPU(s) list: 0-3 Vendor ID: GenuineIntel Model name: Intel(R) Core(TM) i5-7200U CPU @ 2.50GHz CPU family: 6 Model...
  46. F

    Hot air balloon mass including increase in mass with balloon volume

    Hi guys, M can then be split up into 2 components: the mass of the payload which is known, and the mass of the wing. The wing material has a known thickness and density meaning its mass is given by: surface area of wing* mass per m^2 (mass m^2 is used as density and thickness are known so an...
  47. Danny_aero

    Change in potential energy of expanded air in piston-cylinder

    Air is heated in a vertical piston–cylinder assembly fitted with an electrical resistor. The volume of the air slowly increases by 1.6 ft^3 while its pressure remains constant. The area of the piston is 1 ft^2. The mass of the air is 0.6 lb. The local acceleration of gravity is g = 32.0 ft/s^2...
  48. dlgoff

    What are the Styrofoam rods for in the MIG air intake?

    I went to the Combat Air Museum in Topeka, Kansas a couple days ago and thought I'd post a few photos: Inside of turban An old "Air Force One" Inside of hanger 1 of 2 Me
Back
Top