Sound Definition and 1000 Threads

Which of the following of a wave can be affected by the medium it travels through? (i) wave crest velocity, (ii) wave frequency, (iii) wavelength

Hi Likely a stupid question. If atoms vibrate with heat, why don't hot objects make a sound, i.e transferring vibrations to the surround atoms (air) into our eardrums? They vibrate on ultra-infra sound? Or it's a extremely weak sound? or this is not the same vibration as the cause for sound? or...

Homework Statement You are moving at a speed of 35m/s and hear a siren coming from behind you and observe the frequency to be 1370 Hz. The siren goes past you and the new frequency heard is 1330 Hz. What is the speed of the siren traveling at? The speed of sound in air is 340m/s. f1=1370 Hz f2=...

Ok so it happened again... my students asked a question I hand't thought of before (love it when that happens!) Can you help me? What happens to the sound wave after it hits the eardrum? Does it get absorbed, or does it continue to go through your head? I found lots of info about how the...

I'm curious as to why I can hear traffic noise sometimes and not others. The busy hwy is about a mile away across a field. Sometimes it sounds like it is at my door but other times I can't hear it but still see a lot of traffic. How does environmental conditions (temp, no wind, etc) affect the...

Homework Statement \rho_0, c_0 is the mean density, the mean speed of sound in the ideal gas. Is the following correct? c(\rho)=c_0\left(\frac{\rho}{\rho_0}\right)^{\frac{\kappa-1}{2}} Homework Equations p = const * \rho^\kappa, c=\sqrt{\frac{\partial p}{\partial \rho}} The Attempt at...

Hello! I'm new to this website, so apologies if I'm a little off with the way I format this question. Nonetheless: This last year, I've been researching sound energy and methods of focusing, harvesting, and storing this energy. Essentially, I'm looking at the possibility of harnessing sound...

I'm a historian. I've struck on a curiosity about telecommunication technology in pre-modern times. I've read about a number of methods, and I'd like to ask some physics questions that got beyond my ken. This information is for my curiosity and creativity, not for any rigorous study, so I may be...

Taken from my lecturer's notes, how did they make the jump from 8.5 to 8.6 and 8.7? Even after differentiating (8.5) with time I get \rho_0 \frac{\partial^2 \vec u'}{\partial t^2} + \nabla \frac{\partial p '}{\partial t} = 0 \frac{\partial^2 p'}{\partial t^2} + \rho_0 c^2 \nabla \cdot...

This is what I am pondering about: At high altitudes, it makes sense that lower temperatures will correspond with velocity of sound traveling through the air at higher altitudes. With lower temperatures the movement of the gas molecules will slow down, making it more difficult for sound to...

Homework Statement As you drive at a speed of 15.0 m/s an ambulance approaches you from behind with its siren blaring at a frequency of 1022 Hz. After the ambulance has passed you the signal is now 981 Hz. If both you and the ambulance travel at a constant speed how fast was the ambulance...

In contemplation and research regarding another thread's question about the asymmetry of doppler shift wrt the medium, I find myself trying to imagine two people talking... or perhaps better yet matching pitch. In still air with both people facing each other at ten paces of course they would...

i know this is a primitive question and to be answered in my head. eventually both light and sound are a wave carrying information and energy. is speed of light effective to we see it?

Hi All, I am having a problem: no sound coming out of my Windows 8.1 laptop. I updated all the drivers from the audio inputs ; I got the message that the existing drivers were up-to-date, but still no sound coming out and that all sound-related devices are working correctly. Thanks for any advice.

I believe I understand what happens inside an air column that is open at both ends when you cause a disruption such as blowing into it. But I am not sure what happens in the space between the air column and your ear. Please let me explain what my current understanding is and tell me if I'm...

A soap bubble or a nuclear detonation emit a sound created by the sudden release of pressured air? Am I correct? How is the sound of a knock on the door, two billiard balls hitting each other, etc. How is the sound generated in their cases? Thank you.

I know there is a previous post here about this, but it didn't seem to cover the angle I am getting at... I understand sound to be vibrations that travel through a medium such as air or water. However, what actually generates these vibrations? For example, hitting a piece of steel with a rod...

Homework Statement A source emits sound waves equally in all directions. The intensity of the waves 2.50m from the source is 1.9 * 10^-4 W/m^2 a) Find the power of the source b) If the diameter of your ear drum is 8.4 mm, how far from the source do you have to be located, so that your ears...

Hello Guyz I've got a little Question For Seniors I hope You answer it Briefly , I know that whenever i plug in my USB Drive in my Loudspeaker or plug Speaker itself in my PC and play anything like a song an Electrical audio Signal is Produced which is transformed by Speaker into a audible...

Hey guys, It is stated that a 100% perfect square shaped wave have infinite odd harmonics and it is impossible to produced theoretically. But, assuming if a perfect square wave is produced, what would it sound like? I remember someone said it in Youtube it would actually sound like a clarinet...

Homework Statement Estimate the highest possible frequency (in Hertz) and the smallest possible wavelength, of a sound wave in aluminium due to the discrete atomic structure of this material. The mass density, Young's modulus, and atomic weight of aluminium are 2.7x103kg m-3, 6x1010 N m-2, and...

Homework Statement A stone is dropped from the top of a cliff. The splash it makes when striking the water below is heard 2.1s later. The speed of sound in air is 343 m/s. How high is the cliff? Homework Equations Δx=½at^2 t_1+t_2=2.1s t_2=x/343m/s The Attempt at a Solution I used those...

Homework Statement Two speakers (S1,S2), emitting sound waves of frequency 340Hz and separated by a distance of 3 m, are driven by the same oscillator. A listener starts walking from point A to S2 Along the line that joins A and S2> How many points of destructive interference will be observe...

I am trying to calculate the speed of sound in a mixture of 2 gases like oxygen an ozone. First step: I calculated ##\gamma_{eff}## of the mixture by first calculate the ##C_V## of mixture by using a formula $$C_V=\frac{n_1C_1 + n_2C_2}{n_1+n_2}$$ Step 2: in the formula $$v=\sqrt{\frac{\gamma...

Homework Statement Standing 20m away from a tower generating 2500W of power how much energy/s hits each of your eardrums? Surface area of eardrum=55mm^2 Assume that the speaker generates sound uniformly in a forward hemisphere. Homework Equations I=P/(4πr^2) r=20m P=2500W The Attempt at a...

So this is what happened. the thing is that wherever i go i hum. So i was in the bathroom that day and it was as usual tiled everywhere. So when I started to hum, it echoed. Nothing special about it. But as i raised my pitch, there was a pitch at which my humming sound echoed ENORMOUSLY. And...

http://mynoise.net/NoiseMachines/twilightSoundscapeGenerator.php does anyone know how this sound is generated? are do anyone how to reverse engineer? Audacity to record the sound and do a fft ... anyone else know what I can do to reverse engineer this sound?

Hi, I need lessons for sound energy-How tension affects the pitch of sounds for 3rd grade. Thank you

Homework Statement The wire has mass 250g and is tied down at both ends. It has a length of 12.50m and a fundamental frequency of 25.0 Hz. It has linear mass density. Sound travels at 344m/s in air. Calculate the frequency of the sound waves produced when the wire vibrates at its fifth...

Homework Statement A sinusoidal sound wave moves through a medium and is described by the displacement wave function s(x,t) = 2.00cos(15.7x - 858t) where s is in micrometers, x is in meters, and t is in seconds. Find a) the amplitude, b) the wavelength, and c) the speed of this wave. D)...

okay, so I know that light is faster than sound, and we can prove it with many visuals, but can y'all give examples of speeds through the same medium. For example, I know that the speed of sound is 343 in room at 200 C

Homework Statement A small source emits sound waves with a power output 80W. a) find the intensity at a point 3.0m from the source. (0.71W/m) b) find the intensity level at the same point as part a.(118.51) c) at what distance would the intensity be one-fourth as much as of that part (a). i...

Does sound also refract like light? I know it obeys laws of reflection like that of light ( angle of incidence = angle of reflection) How we are able to hear sound when there are doors closed, windows closed etc. Light is eventually stopped by opaque high sized objects. So doors should stop...

If we set two speakers far apart, giving identical sound waves having intensity of threshold of pain, in such a way that at midway between them, there is complete destructive interference. Would there any intensity of sound there in complete silence? If not, then where is "lost" intensity gone...

I am looking at derivations of the Doppler effect for sound and light, and I am very confused about what stays the same when it comes to sound. In this video, at 5:10, it is said that the wavelength will be the same. I'm not sure I agree with this because I'm pretty sure both the observed...

hello! can you explain me please in few simple words, how are we capable to produce sound? in nature, a great variety of different things produces different sounds from the wind on the leaves of the trees, to the huma larynx, a complex organ with numerous muscles yet, all of these sounds...

I am very much into video games. Day Z, Battlefield and stuff like that. In these games it is important to have good headphones so you can hear people sneak up on you, but recently, I have seen ads for 7.1 Surround Sound headphones that actually have multiple drivers in them so that the sound...

Homework Statement The question is as follows, there is a cylinder with length L and radius R, there is a sound wave with a phase velocity v, they ask for the normal modes and the 5 lowest frequencies when L=R Homework Equations Wave equation for 3D, (d^2/dt^2)ψ=v^2*(∇^2)ψ The Attempt at a...

Hello, I'm not sure if this is the place to post this, but I'm hoping that someone here will be able to help me. I am trying to hookup two Sony SS-B1000 speakers to a Klipsch 5.1 system subwoofer (I have attached images of each for reference). I only want to setup a 2.1 system for my PC...

Homework Statement Determine the decibel rating of the following intensities of sound. I = 1.0 x 10-5 W/m2 Homework Equations The equation which relates the intensity of a sound wave to its decibel level is: dB = 10 * log( I / 1.0 x 10-12 W/m2) The Attempt at a Solution dB = 10 * log( 1...

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?

Homework Statement Before I write the question you should know that my maths is all correct in my solution but I must have used the formulas incorrectly (or used the wrong formulas). I can't pinpoint where I've gone wrong or if I have left a formula out (I'm a teacher solving this question for...

I'm having some trouble understand this correctly, so I was hoping someone could enlighten me a bit :) Okay, so in the early Universe most of the hydrogen and helium was formed, and then kept in equilibrium, and ionized via photons. So we have a plasma of baryonic matter, including dark matter...

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...

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 :)

Homework Statement In a test, I was told to identify 3 characteristics that could increase the velocity of the sound traveling through a cup and wire phone. This was a sound and waves unit test. Homework Equations -- The Attempt at a Solution I wrote that the linear density could be...

Hello, I am having a hard time solving this question. Any help is really appreciated. 1. Homework Statement You have designed a new musical instrument of very simple construction. Your design consists of a metal tube with length L and diameter L/10. You have stretched a string of mass per...

A quote from a book: At first, I was under the impression that s_m was constant. But shouldn't s_m be inversely proportional to the distance? The book never says this anywhere directly, but it seems to be implied by two other equations (for the intensity) given in the chapter...

Homework Statement As you stand by a railroad track a train passes with its whistle blowing. As it passes, you hear a frequency shift equal to 21 % of the frequency of the whistle. How fast is the train moving. Express your answer in km/hr.(Speed of sound is 331.4 m/s) Homework Equations f’ = f...

Dear All, Thank you for accepting me at Physics Forum. I wanted to ask a question regarding Sound Dampening of Garbage Chute. The Material Used is REVAC DC1010 AND THE FLAMMABILITY IS AS PER bs 476 .. 1.6 KG/M3. Can anyone explain what is it and how will I define it ? Please find the link...