Air Definition and 1000 Threads

  1. C

    Hard Kinematics problem: Ball thrown into the air

    Homework Statement A person throws a ball up from a height of 1.5 meters, 3.23 seconds later, the ball hits the ground next to you. Find the maximum height the ball reaches. Homework Equations V=V(initial)+at The Attempt at a Solution This problem almost seems impossible without knowing what...
  2. S

    Sound Wave Problem -- time of flight in air versus in water

    Homework Statement Homework Equations v = d/t Solve for t. t = d/v The Attempt at a Solution In my General Physics 2 course we are doing sound waves I have the answer to the problem which is 90.8m I am trying to understand the concepts of sound wave. So please correct me if I am wrong, 1...
  3. T

    B Angle required to hit coordinates x, y, z with air ressitance

    The formula for the angle required for you to launch a projectile with a given velocity, gravity, distance and height difference is, taking g as gravity, v as total velocity, x as total distance on the horizontal plane and y as how high the target is above you (Negative value means the target is...
  4. bob012345

    Maximum Force of Compressed Air

    What's the maximum force that air from a typical garage air compressor tank, the kind that's used to inflate tires assuming the pressure is around 150 psi.? Can the force be changed by nozzle design? Thanks.
  5. jybe

    Mass launched into the air by a spring

    Homework Statement A child's toy consists of a piece of plastic attached to a spring in the figure below. The spring is compressed against the floor a distance of 2.00 cm, and the toy is released. If the toy has a mass of 117 g and rises to a maximum height of 45.0 cm, estimate the force...
  6. K

    Where is the hotter substance? (Dew condensing out of the air onto a lawn)

    1. Let us postulate a warm, muggy, summer’s night on your front lawn. The air is gently settling onto the cooler grass, generating a sparkling coat of dew. 2. Conventional condensation theory tells us that as the liquid dew condenses out of the humid air, a quantity of latent heat is released...
  7. Samuel Scarborough

    Physics Navy or Air Force for Particle Physics

    I have been interested in particle physics since I was in High School, but I have struggled to keep my GPA high enough to get me into grad school and I want to serve my country. I decided that the military was the best route to get the experience I needed. I would like to work with lasers to...
  8. D

    Why does a higher density slow down sound in air?

    Homework Statement Sorry, it's not an actual problem, it's just a statement I don't understand from my text - "The density of water vapor is less than that of dry air. Therefore, the higher the humidity (that is, the more water vapor there is in the air), the lower the density of the air. For...
  9. H

    Varying Gravity and Air Resistance in projectile motion

    Salutations, I have been trying to approach a case about projectile motion considering variation of gravity acceleration and air resistance: A spherical baseball with mass "m" is hit with inclination angle $\theta$ and launching velocity $v_0$, then, the wind has a drag force equals to ##F=kv##...
  10. T

    Solving for final temp of adiabatic ideal air expansion

    Homework Statement Given a problem where air expands adiabatically with a given initial temperature, initial pressure, final pressure, and gamma (ratio of specific heats) , how would one go about solving for the final temperature? I'm just eager to get a general sense of direction. Homework...
  11. D

    CO2 [ppm] exposure relative to room volume [m^3] and air ventilation

    Hi All, I am trying to find out how much CO2 (ppm) would be released into a ventilated room (m3) from a faulty pressurized gas cylinder to calculate risk associated. Would anyone be able to help me with a formula? I was trying to work with V=nRT/P but wasn't sure how do I translate the outcome...
  12. E

    Why does air rise in the water cycle?

    Hi there! I'm teaching about rain shadows to 6th graders, and I've reached a barrier in my content knowledge. For the water cycle to work, warm, wet air near Earth's surface has to rise. In general, warm air is less dense than cold. However, due to air pressure, air near Earth's surface is...
  13. Poetria

    Air Pressure Conversion: Units to Meters

    Homework Statement [/B] dp/dh = -.13*p h in kilometers I should convert it into meters2. The attempt at a solution I thought it would be enough to multiply -0.13 by 1000. :( dp/dh = -130*p but it is wrong.
  14. R

    What is the final temperature of the air in a tube

    Homework Statement I have a copper tube with outer radius r2 and inner radius of r1. Half the tube is exposed to the surrounding air while the other half is embedded into the ground. The outside air temperature is T2 and the ground temperature is T3. What is the air temperature inside the tube...
  15. A

    What is the dynamic viscosity of air?

    Homework Statement Considering an airfoil (a flat plate) flying at 100 m/s under sea-level conditions, so the density is 1.225 kg/m3 and the length being 1 m, what is the dynamic viscosity of air? The problem is that I have two variables in one formula, Reynolds number and the viscosity...
  16. D

    Solving Entropy in Moist Air: No Violation of Law

    Homework Statement When the air outside is very cold and dry, your climate control system must humidify the cabaret air so that the singers don't lose their voices. The climate control let's pure water evaporate into the dry air and raises the moisture content of that air. As this evaporation...
  17. D

    Does Humidity Affect Entropy in Climate-Controlled Environments?

    Homework Statement During the fall, the outside air's temperature is comfortable but its humidity is too high for direct use inside the cabaret. The air feels clammy and damp. So your climate control system chills the outdoor air to extract some of its moisture and then reheats that air back up...
  18. D

    Energy Efficient AC unit by returning air to the building

    Homework Statement You arrange your climate control system so that as it pumps heat out of the cabaret air and thereby chills and dries that air. Part of the heat your system removes from the cabaret air goes to the outdoor air and part goes back to the cabaret air. It turns out that delivering...
  19. D

    What is the chemical formula for moist air at 20°C?

    I am trying to find the chemical formula for moist air. By using an online psychrometric calculator, I find that moist air at 20°C has a mol fraction of water=0.0235 and mol fraction dry air=0.9765. Does this mean like this? 0.9765(O2 + 3.76N2) + 0.0235H2O ----> 41.55(O2 + 3.76N2) + H20 My...
  20. Gregs6799

    What is the formula for calculating the mass of air in a piston?

    Homework Statement Homework Equations pV = (m/Mr)RT (this is the formula given but I got the wrong answer using it) The Attempt at a Solution Mass = PV / RT R = 8.314 P1 x V2 / R x T1 M = 220 x 0.1 / 8.314 x 298 = 788.549kg Mass = 788.549kg P = 440000 V = 0.1 R = 8.314 T = 298...
  21. mktsgm

    Hear Through Walls: How & Why?

    How and why do we hear through the brick walls? Does the sound actually penetrate the walls?
  22. Raihan amin

    Equilibrium height of an air parcel

    Homework Statement An air parcel is investigated to study the weather.It rises up and rests at an equilibrium height in the atmosphere,where its weight is exactly balanced by the upward buoyant force. We shall assume ideal gas law to hold for all processes and neglect the mass of the air...
  23. L

    Heating water and air in a constant volume

    I found a simulation tool on wolfram alpha where the pressure of a constant volume is calculated. The pressure is affected by the heating of a mixture of water and air inside the container. There is an explanation to how the pressure is calculated which seems pretty straight forward. But there...
  24. G

    I Can i create an air flow through a geometry?

    Is there a way to create/force air flow without using electronic components?
  25. russ_watters

    Boeing Lion Air 737 Crash Investigation: Focus on AOA & Airspeed Indicators

    I've been following the Lion Air 737 crash investigation with interest. As is often the case, the media's extremely poor understanding of technical matters makes it a little difficult to follow. One article I raid proclaimed that "the black box" had been found, but the author apparently didn't...
  26. M

    Ansys Maxwell Query: Error "current leak to the air"

    how the error "current leak to the air" in the Ansys Maxwell can be removed? although there is no error in the validation process
  27. Dante Meira

    Repulsion between permanent magnet and air core coil

    I formulated a statement about the repulsion between a permanent magnet and an air core coil (electromagnets without a ferromagnetic or ferrimagnetic core), and I believe this statement is true, but I would like to seek the opinion of others about it: "In a system where an electromagnet made...
  28. S

    Calculating Air Speed Diff. of Plane Lifts

    Homework Statement We have a plane which lift area is A=500 m2 and weight of plane is m= 540 000 kg. That the plane can stay in air the pressure difference between top and bottom of the lifts have to be: B>G --> Δp= (m*g)/A = 10 594.8 Pa. Homework Equations Bernoulli equation The Attempt at...
  29. M

    The dropping of two identical balls without air resistance

    I was thinking about this and couldn't really figure it out. You are standing on a cliff and you have two identical balls. In this case, air resistance is to be ignored. The only thing different is that you throw the ball horizontally at different speeds. Let's say you threw ball one at a speed...
  30. Ramazan Duzgun

    Stopping Light in Air: Myth or Reality?

    is it possible, i mean can we hold it at a certain distance we want ?
  31. A

    MCNPX - How calculate Kerma (kinetic energy released per unit mass) in Air?

    Hi, my name is alexander, i am student from Institute of radioprotection and dosimetry (IRD). My project is calculate MGD (mean glandular dose) from womans with augmented breast. i am having dificulties to calculate Kerma in air with mcnpx. I drew a block of air above the breast, i am using the...
  32. Dr. Courtney

    How Can Doppler Radar Improve Drag Coefficient Measurements in Physics Labs?

    https://aapt.scitation.org/doi/10.1119/1.5064562 The availability of inexpensive Doppler radar has made it practical to accurately measure drag coefficients in undergrad physics labs.ABSTRACT Undergraduate lab design balances several factors: 1) simple experiments connected with learning...
  33. J

    Air Turbine Design -- advice regarding a Hall sensor type air flow meter

    Hello all, I am after some advice regarding a hall sensor type air flow meter. I know from experience that most hall sensor flow meters allow a bypass of fluid around the turbine/fan. However I would like to know what would happen if this was the case of the design below. Specifications...
  34. X

    Free falling ball with and without air resistance

    Homework Statement A 2 kg ball (k factor of 0.02 m-1) is in free fall. The initial downward velocity of the ball is 12 m/s. Find the difference in displacement after 1s both with and without air resistance. Homework Equations vf = vi + at y = yi + 1/2(vi+vf)t y - yi = vit + (1/2)At2 - (1/3)Bt3...
  35. N

    Electrostatics from particle laden air

    Is it possible to generate static electricity from air flow containing particles example smoke or dust flow, or does anyone know of experiments such as the kelvin water dropper converted to generate static from air flow ? Thanks
  36. Fig Neutron

    B Why is there a reverse wind current inside my convertible?

    I was riding home with a friend in their convertible and found that, to my mild irritation, my hair was blowing forward rather than behind me. So, as any logical person would do, I stuck my head out the window to confirm that I wasn’t crazy and my hair should indeed be blowing backwards. After...
  37. B

    Resonant Lengths in open air column question

    Homework Statement An organ pipe 1.2m long and open at both ends produces a note with the fundamental frequency. If the speed of sound in air is 345 m/s, what is the fundamental frequency? Homework Equations Wave equation (f = v/lambda) The Attempt at a Solution My textbook solves the problem...
  38. L

    Why do bubbles of air in water move up?

    What I am confused about is why do bubbles of air in water move up. I understand why solids and liquids would move up in water if they are less dense. I get the idea that the deeper you go in water the more pressure there is because of the more water weighing down on the water and so there would...
  39. john-b

    Why Does Covering One End of a Pipe Change the Pitch of the Sound Produced?

    Homework Statement [/B] When a stream of air is directed over the end of a 40 cm long piece of plastic pipe, open at both ends, a sound is produced. (a) Explain why this occurs (b) If the bottom end of the pipe is covered, what will happen to the pitch of the sound? Explain Homework Equations...
  40. M

    Doubling the time spent in the air by a thrown object

    Homework Statement An object is thrown straight up from the ground and reaches a maximum height of H. How high up do we need to throw the object to double the time it spends in the air? Assume no air friction. Homework Equations ##\Delta x = vt+\frac{g}{2}t^2## The Attempt at a Solution I...
  41. prashantakerkar

    Measuring the weight of gas in an inflated balloon

    What could be the method for measuring weight of gas in inflated balloon? Thanks & Regards, Prashant S Akerkar
  42. A

    Piezoelectric crystal and air pressure

    Will air pressure induce a voltage of a piezoelectric crystal or does it need to be mechanically compressed? My guess is that it would depend on the permeability of the crystal
  43. T

    How to find the velocity of air flow around the aerofoil?

    Homework Statement How to find the velocity of the air flow around the aerofoil? Homework Equations U - freesteam velocity β - angle of wing camber The Attempt at a Solution To find the velocity of the air flow at each section of the aerofoil, am I right to say that the horizontal velocity...
  44. A

    Piezoelectric and air pressure

    I was just wondering if anyone could explain to me what would happen to a piezoelectric crystal on a closed circuit in a pressurised vessel?
  45. I

    A five-liter pot is filled with 2 l of liquid water and 3 l of dry air....

    Homework Statement A five-liter pot is filled with 2 l of liquid water and 3 l of dry air at the ambient pressure of 1 atm and temperature 10◦C. Subsequently, the pot is closed and heated up. What is the pressure inside the pot going to be when the temperature reaches 100◦C? Homework...
  46. Gregs6799

    The mass of air in the pressurised air tank

    Homework Statement A pressurised air tank supplies compressed air to an air engine. When the air engine is not running the absolute pressure in the tank is 300 bar and the temperature of the air is 60°C. Calculate: (a) The temperature of the air in the high pressure air tank when the air...
  47. J

    Power required to compress air in a gas turbine

    I'm looking for advice on how much power is required to compress air in a gas turbine engine - parameterised by degree of compression and mass flow. Normal gas turbine engines have exhaust turbine(s) on the same shaft as the air compressors. They bleed some of the exhaust energy to drive the...
  48. Fabrizio Vassallo

    Weight of a box with a flying bird

    Hello! This is my first post here, and I look forward to many more! This is a sort of riddle I was told today, and left me full of doubts. So, the 'puzzle' was the following: " There's a man carrying behind his truck an enclosed trailer full of birds inside it. All the birds are standing on...
  49. S

    Air resistance in projectile motion

    In lower-division physics classes, air resistance is usually ignored to make the mathematics of projectile motion easier to understand. When air resistance is included, it's often stated that at lower velocities, air resistance is proportional to the velocity of the object, Fair ∝ kv At...
  50. bob012345

    How much air flow is required for lifting a wing?

    Given a wing that lifts a plane moving through it at velocity V, how do I figure the minimum volume of air flow necessary to lift the same wing if the plane is still and the air is blown over it? Would moving that volume of air over the wing artificially require more power than what is required...
Back
Top