Air Definition and 1000 Threads

  1. H

    A=F/M Based problem - air track glider

    At time t=0 s a 0.362-kg air track glider is moving rightward at 5.1 m/s. At t=2.5 s, it's going leftward at 5.4 m/s. Determine the magnitude and direction of the constant force that acted on the glider during this interval. Give your answer in Newtons. If the force is going rightward, your...
  2. B

    Calculating flow of air from explosive decrompression

    Hey! Making a game. Say we have a room of 8*12*3 meters. It has the pressure of 1 atm and suddenly there's a hole of one cubic meter in a wall and outside it's space vacuum. Don't know if it counts how much air is inside the room or if that would be measured in pressure, say we have enough...
  3. A

    Air Track Elastic Collision: Solving for Final Velocities

    Homework Statement A 0.159kg glider is moving to the right on a frictionless, horizontal air track with a speed of 0.870m/s . It has a head-on collision with a 0.310kg glider that is moving to the left with a speed of 2.15m/s . Suppose the collision is elastic. a) Find the magnitude of the...
  4. M

    Calculating velocity of a bullet with quadratic air drag

    So this problem was a 2 part question. The first part goes as such. 1. A gun is fired straight up. Assuming that the air drag on the bullet varies quadratically with speed, show that the speed varies with height according to the equations: v2 = Ae-2kx - (g/k) (upward motion) v2 = (g/k) -...
  5. E

    What do we mean unit SCFH AIR ?

    Hi. What do we mean unit SCFH AIR ? how can convert to m3/hr?
  6. MexChemE

    Psychrometry -- Ethanol in dry air

    Homework Statement Ethanol evaporates in a 10 x 20 x 50 ft3 room. Air is initially dry at a temperature of 30 °C and 765 mmHg of pressure. a) If the partial pressure of ethanol after vaporization is 40 mmHg, how many pounds of ethanol evaporated? b) The same air is compressed until it reaches a...
  7. Ascendant78

    Motion of a mass of air around Earth.

    Homework Statement Homework Equations The Attempt at a Solution For starters, I am a bit confused about how to work on this problem considering the only relevant equations given for this problem (in the chapter we are currently in) are the two equations for Fr and Fφ for a 2-D polar...
  8. M

    Macbook 13.3 Pro vs Air: Price vs Performance for Research Needs

    I'm looking into getting a laptop this summer if I'm able to get into an REU. I was looking at macbooks, just because they are reliable, have long battery life, and still has the power I need for programs like Mathematica or Sage, since it will be used for research, the computing will probably...
  9. A

    Vector Calculus: Air flowing through loop of straight lines

    Homework Statement Air is flowing with a speed v in the direction (-1, -1, 1,) calculate the volume of air flowing through the loop consisting of straight lines joining (in order i presume) (1,1,0) (1,0,0) (0,0,0) (0,1,1) (1,1,0) Homework EquationsThe Attempt at a Solution I assume you have to...
  10. M

    Calculating Density of High Altitude Air Using Ideal Gas Law

    Homework Statement Treat the atmosphere as an ideal gas with a uniform temperature of 200 K. Find the density at 20 km. R= 260 N*m/(kg*k) g= 3.92 m/s^2 rho(0)= 0.015 kg/m^3 Homework Equations P=rho*R*T dp/dz= -rho*gThe Attempt at a Solution I found the pressure at ground level using...
  11. Scott Davies

    Easy way to find the potential energy in compressed air

    I have a .81 Cu. Ft. cylinder which is at a static pressure of 80 Psi. What is the easiest way to calculate the Potential Energy of the compressed air?
  12. I

    Work done by Air resistance on ball?

    Homework Statement Hey! Problem: A ball falls 8,5 meters, and hits the ground with 11 m/s. The ball has a mass of 0,2 kilos. How much work was done by Air resistance on the ball? Homework Equations I guess mechanical energy eqution? The Attempt at a Solution answer should be -4,5 joule...
  13. J

    Need suggestions on transfering compressed air to rotating object

    If you had a rotating object like a tire or barrel that you wanted to distribute compressed air to while it's rotating, what would some ways to do it? One way I'm thinking is just a tight seal at the axis, but then there would be a lot of friction. Any other ideas??
  14. J

    Can air pressure stop in a pipe?

    Hi guys Im trying to understand something.. If air is coming through a pipe, at a variable fan speed. (0.0053 m3/s) and the pipe is 10 meters long and coiled. Will the air reach the end of the coil? Or can air just loose pressure at a certain point? Thanks!
  15. supak111

    Laser to ionize air to run current, laser power per foot?

    Hey guys I know that a laser can ionize air so that you could run current through air. I was wondering if anyone could tell me just how powerful (watts) the laser would have to be If I wanted to connect 2 point that are about 100 feet apart? 2 points have very low current but do have high...
  16. Christina H

    Calculations for cooling a volume of air

    Hallo, Working on building a cloud chamber based on thermoelectric coolers rather than dry ice or other "consumable" cooling methods, and having some difficulty working out some of the numbers. Say I have a volume of air at room temperature, for arguments sake 1600cm³, and I want to cool this...
  17. K

    Calculating the force air has on an object

    I am trying to calculate the force that compressed air has on a cylinder. These cylinders are pushed in a production line for transportation using air. I would like to calculate the force such air puts on the cylinder. I have the velocity of the air, the área of the cylinder. Will using the...
  18. S

    What is the velocity of the air flowing though the pipe?

    Homework Statement The horizontal pipe is very large and long: 100 feet in diameter and 1500 feet long with an infinite supply of air on both ends. The pressure difference between the two ends is 0.6 psi. I assume friction is near zero as the pipe is so big so I ignore it. What is the...
  19. P

    Projectiles in Air: Is Under Spin Enough to Rise?

    Is it theoretically possible to get a round bullet to rise if shot horizontally provided the bullet ( projectile) is given "under spin"?
  20. M

    Air flow over a circular cylinder

    Hi, Could you explain the reason why the velocity varies in the wake region behind the cylinder in "flow over a circular cylinder"? the velocity variation is, minimum at a point parallel to the centre point of the cylinder and increases to free stream velocity as the vertical distance increases...
  21. R

    Why is my time calculation for the ball's flight incorrect?

    1. A ball is thrown vertically upward with an initial velocity of 27.0 m/s. Neglecting air resistance, how long is the ball in the air?Homework Equations vf (v final) = v0 (v initial) + at[/B]The Attempt at a Solution I set final velocity equal 0. So.. 0 = 27.0 m/s (initial velocity) +...
  22. T

    Required water pressure to find air leak

    I have an air leak somewhere in a coil or 20 feet of pipe in a mechanical room next to a transformer. I have 160 psi of air on the system and it dropped 30 psi in two days. I have tried to find the lead with 60 psi of water currently but no success. I do not want to put a lot of water...
  23. K

    Thermodynamics problem - Compressing the air. Energy Balance

    MODERATOR NOTE: THIS THREAD WAS ORIGINALLY POSTED SOMEWHERE ELSE, SO THERE IS NO TEMPLATE. Dear! I have a problem with one, complex exercise. I’ve divided it into three parts just to simplify finding the answer. So let’s start. The air is sucked from the atmosphere by a compressor. Atmospheric...
  24. Z

    Speed of sound in turbulent air?

    If I turn on a standing fan in my room how does the speed of sound change in the fast moving air compared to the still air around it? Would it be relatively faster, slower, or does it depend on the direction in which the fan is blowing?
  25. K

    Air machine and compressed air

    Homework Statement Air at pressure 20[atm] enters an air machine and leaves at 1[atm]. what must be the temperature of the air at the entrance so that when it leaves it is 00C. Assume adiabatic process. Homework Equations PV=nRT Adiabatic: ##P_1V_1^\gamma=P_2V_2^\gamma## The Attempt at a...
  26. P

    Which gas model to use for dry air and N2 at 300 bar

    I want to calculate the change of state for N2 and dry air at pressures above 200 bar with a max of 300 bar. Ideal gas law is not applicable at these pressures, but looking at real gas models there are several to choose from, among others: Van der Waals Redlich-Kwong Virial Bender Can someone...
  27. K

    What Is the Temperature of Compressed Air in a Diesel Cylinder?

    Homework Statement At the start of the compression stroke, the cylinder in a diesel motor contains 300[cm3] of air at atmospheric pressure and 270C, and at the end of the stroke the volume is 20[cm3] and manometric pressure 41[atm]. What is the temperature. Homework Equations...
  28. W

    Air valve operated by permanent & electro magnet

    I am looking to open a series of valves in a chamber under 10" of lift(water) ~.36psi which are normally held closed by a very light spring and the constant air pressure. The valves are very light weight and range in surface size from approx 2 to 6 sq inches, or approx .72 to 2.16 lb of initial...
  29. M

    Calculating the force of air entering a vacuum

    There is a metal cube that is any size desired. the contents of the cube is a vacuum of space. there is a tube that is also a vacuum of space that also can be any size desired. The third item is a ball that fits air tight in the tube perfectly at the furthest point from the ball. The ball can...
  30. T

    Extremely high loads when 100% ouside air is used in HAP

    When calculating the cooling load of a lab,when i put 100% outside air in the ventilation section,the loads seem to leap extremely high (more than 4 RT above what it would be in a normal situation).I understand that the high volumes of unconditioned air would increase the load significantly.The...
  31. K

    Pump compresses air into a tank

    Homework Statement A cylindrical pump of length 25[cm] pumps air in atmoshpheric pressure ant temp 270C into a big tank. the manometric pressure in the tank is 4[atm]. at which distance will the air start entering the tank. Homework Equations In adiabatic process...
  32. A

    Settling the Debate: Air Compressors & Koi Ponds

    I wonder if someone can help settle a debate I am having over using air compressors to aerate garden koi ponds? A typical pond will have a small electric air pump (44W rated, delivers say 50 litres a minute at 1.5 metres deep in a 10000L pond) blowing air through a diffuser to add oxygen and...
  33. K

    Air is compressed in a cylinder

    Homework Statement A cylinder of height 1[m] has a weightless piston on it's head. mercury is spilled slowly on the piston and it goes in. at what distance will the mercury start to spill over the cylinder. the process is at constant temperature. Homework Equations $$PV=nRT$$ At constant...
  34. stephenranger

    Using Compressed Air Tools Outdoors: Can it be Done?

    Homework Statement Car mechanics use compressed air tools to open bolts. Instead of using an air compressor one can also use a tank of pressurized air. There is an air tank with a volume of 50 L to work with. The pressure of the tank is 50 bars when it is stored indoors at 20 °C. The bolt...
  35. N

    Caculate air flow using tank pressure

    Dear all ! I am an engineer from Vietnam! I just started to work 4 months ago. Now I got assignments with compressed air system! The compressor is not mentioned here! We have an air vessel of 500 Liters, and pressure is 7 bar. Before air vessel is an air booster with inlet pressure of 6 bar. The...
  36. StevieTNZ

    News Air Asia flight from Indonesia to Singapore vanishes

    http://www.stuff.co.nz/world/asia/64507189/air-asia-flight-from-indonesia-to-singapore-vanishes If it lost contact at 11.17am NZT, and it is now 6.12pm NZT, that is way over six hours that it has been missing.
  37. F

    Novice Electrical Guy with a Mechanical Question

    Hello All. This is my first post, and I hope it is not too simplistic, but I am out of my normal line of work here. I am trying to understand the relationships between flow, velocity, and cross sectional area with gases and fluids(air and water). Imagine a large vertical, cylindrical tank...
  38. profinger

    Air turbine? to increase air speed/compress air

    Is there such thing as a turbine that increases air speed/compression? This seems like a dumb question but I'm having a heck of a time locating any information on it because any iteration of "air turbine" entered into Google just brings up information about wind mills. I'm looking for something...
  39. F

    Determining the speed of sound in air

    Hello! I have a problem with determining speed of sound basing on a data from laboratory. 1. Homework Statement I have to determine speed of sound by measuring the shift of time in microphone compared to speaker. The distance between them is constant and I'm changing the frequency in...
  40. J

    Would it be possible to hold electrified liquids in the air?

    Hi, Would it be possible to hold electrified liquids in the air? There is an external electric field applied to the liquids. What kind of liquid must it be? I guess water wouldn't do the job.
  41. Paulene Gueco

    Speed of Sound in Air as a Function of Temperature

    Hi, guys! :) I do hope I am posting on the right thread here. So anyways, I'm looking into a certain topic: "Speed of Sound in Air as a Function of Temperature". Any thoughts on how I could do this experimentally? Warm regards, Paulene :)
  42. C

    Calculating time required to pressurize compressed air tank

    Hello, I searched as best I could but could not find a direct answer to my question; I've seen similar questions but without the required data to be able to make the calculation. I thought this would be a simple calculation to find but apparently not. Compressed air source is 4.46cfm @ 93psi -...
  43. quantumlover

    How does the Clair air purifier's e2f filter affect fan sizing?

    I recently shifted to South Korea to pursue higher studies and stay with my sister and niece . My niece is working on a high school project on air pollution and indoor air quality studies . Starting with a write up on air pollution and then indoor air quality and effects on health and the...
  44. P

    Can Different Electrodes Affect Air's Dielectric Strength Values?

    Hi, Am I correct in thinking that for a medium such as air, the dielectric strength is a property of the material and as such has a single value for that material? The reason I ask is because I have been testing the breakdown of air between different types of electrodes and because the...
  45. T

    Termodynamics: saturation pressure vs total air pressure

    Hi! I have a question. The experiment goes like this. i hermetically close air and chloroform at standard pressure. now i want to calculate the end pressure of gas mixture after chloroform vapor gets saturated. is it as simple as adding up the chloroform saturated pressure to the starting air...
  46. R

    Air Jet Fluid Mechanics Experiment

    Hi all, Recently did a lab experiment where we had a nozzle pointing vertically upwards at a flat plate normal to the direction of the flow of air. The plate had a spring gauge on it so that the force of the air on the plate could be measured. The plate was moved to various distances above the...
  47. R

    Performance Test Air Flow Restriction At Work Shed Louvers

    At work we have a shed in full sun. Windows were cut in it to allow airflow. Louvers were installed to keep the rain out. However the sheet metal guys did a HUGE overkill on designing the louvers. I want to propose to my boss to remove half of the louvers so that we can get decent air flow...
  48. R

    Cryogenic liquification of air (Linde process)

    Does anyone know what pressure air has to be compressed too so that the JT effect causes the air to liquify? I am running a simulation and I have the pressure up to 9000 psig and 0F and the drop in temp is only to -125F. The requisite temp to liquify air is ~ -320F from my simulation results...
  49. R

    Lightweight Tubular Frame: Can it Float?

    Can you use a vacuum, or lighter than air gas within a tubular frame network to neutralize the apparent weight of the frame? If this is possible what is thee smallest possible size you could make this frame, I understand that the more you scale it up the lighter proportionately the frame would...
  50. A

    Air pressure stays the same or increase?

    the barrel has a lid at the top...sealed. I make a hole at the bottom to attach water hose to it. Then I turn on the water hose. The water volume in the barrel increases, no doubt about that. When It takes 7/8 of the barrel. Will the air in the top 1/8 of the barrel be compressed? I ask because...
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