Sound Definition and 1000 Threads

First off, I'm new here so I'll do a brief introduction: I've never taken a physics class, but am taking AP Physics next year (didn't know they offered it at my high school). I'm also a musician and wannabe engineer, so I'm really interested in sound properties, acoustics, etc. So that's me...

If vibrating object produces sound in air and there's a solid object in front of it after some distance, will those sound waves(which were propagating in air before) start propagating within that same solid object or reflected or absorbed or etc. Please explain also. Thanks.

This is my first post on here, so I apologize in advance if I'm in the wrong section or something. I was thinking about having this as my schedule for the fall semester. -Analysis I -Discrete Mathematics -General Physics I -Data Structures I'm not sure if I'm being overly ambitious...

1. Two identical strings on different cellos are tuned to the 440-Hz A note. The peg holding one of the strings slips, so its tension is decreased by 1.5%. What is the beat frequency heard when the strings are played together? f₁=440Hz; Tension decrease=1.5%2. f(beat)=|f₁-f₂|3. f₂=440Hz -...

Hello Forum. I have two basic sound questions: I know sound (large wavelength) diffracts a lot when it exits an aperture. But if someone is speaking and he/she is not facing us we still hear them, even if we are in an empty field. Does sound diffract so much that it ends up even behind...

I've seen stated in many a physics book that the general case for the speed of sound (for general equations of state p(ρ) ) is given by c^2 = \frac{\partial p}{\partial \rho} where p is pressure and ρ is density. but I can't for the life of me figure out how on Earth to derive that...

first thread, sorry if its in the wrong place. I can't find anything about this but it seems logical none the less. I was watching something where a noise was heard and then a plane flew by. Assuming it was a train, to make it easier, and you hear a train whistle and your on the track you...

The deciBel is probably the most commonly used unit for sound, but why isn't there an SI unit? Also, what is a logarithmic unit? Thanks.

If amplitude is the measure of energy in a sound wave - On increasing amplitude, the medium particles should hit each other in lesser time because they have more force(which increases their speed) and this cycle should repeat and repeat. Eventually, the speed of sound should increase. But...

Please excuse me if this is not the most appropriate subforum for this question and please move it if necessary. I am trying to make a numerical model with Mathematica to synthesize the sound of a struck drum head (circular membrane). I solve the wave equation for a circular membrane to get a...

Homework Statement the laws of refraction and reflection are the same for sound as for light. the speed of sound is 340 m/s in air and 1510 m/s in water. if a sound wave traveling in air approaches a plane water surface at an angle of incidence 12°, what is the angle of refraction? Homework...

How to read a signal through the sound card? I want to capture an amplified electric signal that emerge in the heart, and then to draw the ECG diagram. Can I use the soundcard's jacks for this purpose? if then, what is the best method to use to capture these signals using C++ on windows...

I am the least of a 'physics' person yet I find myself here, It is very cold just now in eastern Poland. for a week -20C - 4F very sunny and dry Why do the nearby church bells (100 meters?) certainly have a different sound/higher tone to my ears at least now in these low dry high pressure...

Hi, I would like to know if anyone knows where can I find people who do certification of Sound Level Meter (Not calibration). I need to certify my Sound Level Meter to IEC 61672. Please provide details if you know who can do it. Thank you. Best Regards, Richard

Homework Statement A jet is flying horizontally [drawing shows an observer on the ground, a plane overhead at point B, and an outline of the plane from it's observed position to the left at point A. The angle between the observer and point A is 36°.] When the plane is directly overhead at B, a...

hello, i am involved in a private project. for this project it is necessary to control a huge amount of loudspeakers (intensity, frequency) in order to achieve beam forming of the sound waves. However, since i am not an electrical engeneer i really do not have a clue how something like this...

Homework Statement One microphone is located at the origin, and a second microphone is located on the +y-axis. The microphones are separated by a distance of D= 1.21m. A source of sound is located on the +x-axis, its distance from microphones 1 and 2 being L1 and L2, respectively. The speed of...

I am considering applying spray-on acoustic/popcorn ceilings to reduce the noise level in my house. I haven't found any data supporting that popcorn ceiling reduce noise level. I am looking for data, physics, experiments, and tools to help me figure this out. I asked this question at...

Homework Statement a noisy machine in a factory produces a decibel rating of 80 dB. how manyidentical machines could you add to the factory without exceeding the 90-dB limit? Homework Equations I=P/A and B+10log(I/I(sub)0) ... (I think) The Attempt at a Solution I tried to find...

Homework Statement http://dl.dropbox.com/u/11341635/IntegrationProblem.jpg Homework Equations http://dl.dropbox.com/u/11341635/Fourier%20Transform%20Equations.jpg The Attempt at a Solution http://dl.dropbox.com/u/11341635/1st%20part%20of%20attempt.png...

Homework Statement No specific question, I'm a greenhand to waves, so when it came to sound cavity, I was just confused how the teacher(in the video lecture,I'm not a physics major) can distinguish which side is a node and which is an anti-node, it seems too fast for me, could anyone give me a...

Homework Statement A jet is flying horizontally, as the drawing shows. When the plane is directly overhead at B, a person on the ground hears the sound coming from A in the drawing. The average temperature of the air is 20 oC. If the speed of the plane at A is 180 m/s, what is its speed at...

I'm doing a project on a water xylophone, and I have a couple questions about it. Please site your sources because we need all the help we can get. Thanks =D 1) How does the shape of the glass affect the sound the water produces. 2) Why does more water in a glass lower the frequency of the...

Thank you for the help!

Speed of sound The speed of sound c in a gas depends on among other things on the pressure on the gas, the density and probably, possibly on their viscosity. Determine c- My Variable list: Pressure p ML^-1T^-2 Density ρ ML^-3 Speed v LT^-1 My matrix: | | M | L | T | | p | 1 |...

wrt means with respect to Homework Statement see attachment that contains full question. firstly read paragraph then see on question. The Attempt at a Solution velocity of sound will be 340ms-1 wrt air or ground(since air i snot blowng). Now speed of soud wrt train A= speed of sound...

A submarine sonar system sends a burst of sound with a frequency of 325Hz. The sound wave bounces off an underwater rock face and returns to the submarine in 8.50s. If the wavelength of the sound is 4.71m, how far away is the rock face? (Ans: 6.51km ) -- v=fλ λ=wavelength f=frequency...

I would like to do some audio programming for a school project, but I'm not sure how a computer processes audio and reconstructs it in a sound card. I've had a signal processing course that covered standard DSP topics but I'm not sure when or how they are applied to acquire, store, and...

Knowing that its possible to break a glass if you emit a loud sound at its resonant frequency. If you do the same for Human skulls, there will not only be a sound sleep, but a sound death too. Is that possible?

hi i have a physics questions about sound Sound waves are used to detect faults in girders. a cro is used to detect these faults, a pulse producer and a detector is placed on opposite sides of the detector. The safe detector has a upwards spike at 0microseconds and at 10 microseconds. The...

[PLAIN]http://postimage.org/image/4ure9j3sr/1. Homework Statement i have a physics questions about sound Sound waves are used to detect faults in girders. a cro is used to detect these faults, a pulse producer and a detector is placed on opposite sides of the detector. The safe detector...

Homework Statement A jackhammer with a sound power of 10 W is operating in the countryside. Calculate the intensity levels at distances of 2.0 m and 50.0 m from the jackhammer. Calculate the corresponding levels in dB. Homework Equations β = (10dB) log (I/Io) where, β = sound...

A laser beam and a sound wave from directional sources both enter a liquid at an angle of 60 degrees from the horizontal surface of the liquid. The speed of sound in the liquid is 1.8 times that of the speed of sound in air. For light, the refractive index of the liquid is 1.8. What happens...

hi could somebody explain to me how organ pipes work? so far, i figured out that there are standing waves in an organ pipe, that are determined by the length and the question of whether there is a closed or open end. but what determines the intensity between these possible frequences(e.g...

Homework Statement In room temperature air, which of the following sound waves would have the greatest energy associated with it? A. A wave with lambda equal to 4.7 on B. A wave with a frequency of 2.6 Hz C. A wave which has a distance between adjacent nodes (1/2lambda) of 21mm...

I understand that an object can exist in many possible locations, and that when you're not looking, it is a wave. It's only when you look that it manifests itself into a particle. But Is that also dependent on the measurement of sound? Does an object materialize when you hear it, or feel a force...

When I was younger I had a ball on a string. For what it's worth, the ball was quite a dense rubber, and about two inches in diameter and spherical, so I think it weighed about two-and-a-bit ounces, maybe two-and-a-half. The string was about a metre long, and it was very stretchy... Once I...

What is the difference between sound and music? What is the basic property of music?

This is not a question as such, but it's for answering a homework question. I understand how stationary sound waves in a closed tube are formed, as they reflect off the closed end and the two waves traveling in opposite directions interfere to form a stationary resultant wave (that's how I was...

Amplitude Of Single Tone Sound Wave = "Loudness"? Hello, Given a single tone sound wave: x(t) = A * sin( 2 * pi * freq * t ), what does the 'A' actually represent? Peak Intensity? Intensity Level? Peak Amplitude Pressure? What is adding to my confusion is this link...

Okay, so I have a sound wave (a visual representation). From this I can see the amplitude of the wave, However, I need to know what the sound power or the sound pressure level. Could someone please give me a formula that could help? Thanks

I want to be able to figure out how sound works down a tube. Leading to me being able to calculate where I should place slits on a tube and at what size given a tube diameter (and length if necessary) to make a good shotgun mic tube. The slits allow wave cancellation. So there is some...

Not sure which section to post this in, but here goes. It's entirely my own words - might look like homework but it's for electronics. Multiple microphones are connected to a computer. A sudden sound, like a gunshot, goes off in the distance. These microphones are separated from each other by a...

If a sound frequency is given at 1800Hz, how can I determine what range of low frequency would create a harmonic or non-harmonic (which is opposite with harmonic) vibration with 1800Hz? Thanks in advance for any suggestions

A student typing in a computer cluster generates a sound level of 55 dB. What will the dB level the night before essays are due when there are 30 equally noisy students working in the cluster? dBo = 55 Ihearing = 1E-12 W/m2 Bo = 10log(I/Ihearing) 55 = 10log(I/Ihearing) 55 =...

Hello there, I'm making a presentation on the speed of sound in a few days and I was wondering if anyone knows where I can find a video that shows a (preferably huge) explosion from a distance with a timer on it. What I wish to convey from this video is the fact that the light from the...

Homework Statement You are standing in between two sets of railroad tracks. On one set of tracks a train is initially 200 m away and approaching you with a constant speed of v0 = 11 m/s. On the other set of tracks second train is at the same distance and moving away from you at the same...

Does anyone have any suggestions on what device can measure sound frequency below 20 Hz? Thanks in advance for any suggestions

When you try to listen to music through headphones you can reasonably hear the low end (lower frequencies). When you take the headphones off of your head and place them far enough away you only hear a tinny sound. When you are outside of a loud rock concert, maybe 1500ft from the source, you...

Homework Statement I had a Physics lab with the following setting: A signal generator is connected to a speaker which is located on one end of a tube. This creates the sound wave. The tube is open on both ends. A micro is movable along the tube and it is connected to an occsilator which...