Sound Definition and 1000 Threads

Homework Statement Sound 1 has an intensity of 39.0 W/m^2. Sound 2 has an intensity level that is 2.5 dB greater than the intensity level of sound 1. What is the intensity of sound 2? Homework Equations I=energy/area*time β=(10dB) logI/Io Io=10^-12 W/m^2 The Attempt at a Solution...

Homework Statement Lighting strikes the ground 1.00 km form an observation point. Calculate the delay between seeing the flash and hearing the thunder. (Temperature @ 15⁰C)(Speed of light = 2.99 x10⁸ m/s) Homework Equations v=331+(0.6)T The Attempt at a Solution Speed of the...

Hi, I'm doing some research on sound. I'm interested in finding out what happens to a sound wave just BEFORE it reaches a black hole and what happens when it ACTUALLY reaches a black hole ? Can someone direct me to the right place for this ? Thanks for the help

what's difference of sound velocity in a stationary fluid compared to a moving fluid? regards

What would happen if an air pressure increase from one sound wave were located at the same place and time as a pressure decrease from another of the same amplitude?

I've preformed an experiment about the speed of sound waves in water and I found that sound traveled faster in hot water than cold water (distilled water), but it traveled still faster in salt water. So, how can I explain why the speed of sound increases with salinity? We have the equation: c=...

I am wondering if sounds would be noticeably different inside of a tunnel made out of ice than for a tunnel made out of dirt/planet's crust. If so, can you think of any comparisons or general differences. For instance, would sounds echo louder/farther in one of them? I suspect the properties...

Hi there, I am currently got a little project in my head, and though I am good at science i don't know enough physics to work this solution out and i was hoping someone would be able to help. Now i know sound wave diminish over time, but by how much and how fast, here my problem if i...

Hi, I would like to know about what exactly constitutes a shockwave. Let me write out what I understand of it. There are two explanations I have come across. 1) The shockwave is caused when gas particles move faster than the speed of sound due to some external factor (a plane, an explosion or...

Homework Statement Shown in the picture attachment. The Attempt at a Solution Hello! with this question I am just completely lost. I haven't the slightest clue how to get started. Anybody care to explain why the answer is D? (I've looked at the markscheme..)

The following is part of an experiment about the speed of sound in different depths of a liquid, I'm trying to solve it in Matlab. http://img546.imageshack.us/img546/5952/20120408201206.jpg Here is my attempt: clc clf N=13; d=1900:-100:700; t=[2.62 2.37 2.35 2.25 2.09 1.86...

Hey guys, I have an average-man knowledge in physics so please simplify your question so anyone could understand :) I had no place for this so I'm writing it here in the general forum.I asked a friend of mine if you can supress sound waves entirely, so you won't hear a thing. to keep things...

Help: Sound created over/in subspace? (SciFi) I know nothing, called basic high school physics and chemistry. However, do not hold back in your answers I do find ways to comprehend what people tell me. This might be a silly question but since audible "sounds" can't travel over empty...

What frequency of sound traveling in air at 11 oC has a wavelength of 4 m? From what I can come up with... the frequency of sound at 20C is 344 m/s and at -20C is 320 m/s. From this I interpolated and got at 10C it is 332 m/s and then kinda guessing at 11C it is 333.2 m/s. 333.2 / 4 m =...

Homework Statement A bird watcher is hoping to add a particular song bird to the list of species she has seen. If a person, only 2.35 m from the bird, hears the sound with an intensity of 1.9 10-6 W/m2, how far could the bird watcher be from the bird and still hear it? Assume no reflections or...

Ok, I applied for 10 chemistry REUs this year. I have only heard back from a couple of them so far, but both were rejections. Now, obviously I still have a lot of opportunity to get a different one, but right I'm just sitting here wondering why I wasn't accepted. Going into senior year 4.0...

Hi all i am now prepar to write a essay about use sound to put off fire, and the pre-reserach i have done have show that the sound do can put off fire, however the very low efficient. What i want to find out how can i extend its distance to put out fire, i have try something ,and some of them...

'speed' of sound vs. 'feel' of sound? (e.g. subwoofer, tree falling, etc.) When bass plays from a subwoofer, a tree falls, a bomb explodes or something similar there's a very real physical sensation that accompanies the sound. My mind is most curious to know if these travel at the exact same...

Homework Statement Standing sound waves are produced in a pipe that is 1.40 m long. For the fundamental frequency and the first two overtones, determine the locations along the pipe (measured from the left end) of the displacement nodes if the pipe is open at both ends. Homework...

Hello, I want to use and oscilloscope to demonstrate sound waves for our local school science day. I want to be able to allow kids to make different vocal sounds to see how the sound waves look like. I removed the microphone part from a headphone and used it in a circuit to see audio...

Hello. I'm trying to make an LED light to carry sound, in a simple blink-it-like-it-arrives way. The problem is, on the receiving end the sound arrives with a lot of distortions, most apparent in the lower notes. Single tones are reproduced faithfully, but anything more complex sounds like...

Homework Statement A tube is closed at one end by a piston which is slowly withdrawn as a tuning fork of frequency 512 Hz is sounded over it. What is the shortest length of pipe which will resonate with the fork? (Speed of sound is 340m/s) Homework Equations L=1/4λ f=v/(4L) The...

Hi all, I was just reading a bit on the disc reading. It was only then that this idea of using sound to read discs struck me. We know that sound too, behaves like light, in many situations(has a particular speed limit, both exhibit resonance, etc.). One very important difference being that...

Hello Forum, I am planning to buy a noise meter. This instrument receives a signal that carries a certain total power. A spectrum analyzer tells us how this total power is distributed among the various frequency components. When the sound meter gives a reading in the dB (A) scale it is...

Total Power output Sound! All right, nevermind, problem resumed. . A rock band has an average intensity level of 110 dB at a distance of 15 m from the speakers. Assuming the sound is radiated equally over a hemisphere in front of the band, what is the total power output? Relevant...

Homework Statement A rhinoceros is calling to her mate using sound wave whose frequency is 5.0 Hz. Her mate is 480 m away. The air is 35°C. How many wavelengths of the sound are between the two animals? Homework Equations v = 331 + (.6)*T v = wavelength*frequency The Attempt at a...

Is there an equation that deals with the dissipation of sound waves in air? As in, how much they die out with distance, because we know they must, otherwise you could hear me talking now!

Homework Statement 17.While cruising the North Atlantic in a fog, a ship blew its horn, and received an echo from an iceberg 4.0 s later. The temperature of the air was 5°C, the temperature of the iceberg was 0°C, and the temperature of the water was 2°C In order to calculate the distance...

Homework Statement A student standing on top of a cliff drops a rock down below into the water and hears it splash 3 seconds later. The speed of sound is 330m/s, what is the height of the cliff Homework Equations v= d/t v2 = v1 + at d = v2-1/2 at2 d = (v1 + v2)t v2 squared = v1...

Hi, I'm doing a lab report and I need to know if ultrasound speed in the air is the same of sound speed in the air. Thank you

Does anyone have an explanation for why kinetic energy carried by electromagnetic radiation travels at the speed of light? My understanding of the speed of sound is that the denser the medium, the faster the wave velocity. Since this is just kinetic energy propagating through a medium, how is...

Homework Statement Assume the air temperature is 10.8o C, and the speed of sound in air is 337.8 m/s. Suppose the lab floor is 2.61 m beneath the motion detector. If the detector produces a click, how long would it take before the echo returned? Homework Equations s=Vi*t +...

I have always been interested in light and sound design (mostly at concerts) and was wondering how could i get into a job or something that will help me get involved into that field ? i don't really want to go through my schools theature program just because i don't like it but yeah help me

We know that speed of sound in liquid is more than in air. Also, velocity of sound = wavelength X frequency. Now there's a change in speed of sound from air to liquid, so, wavelength or frequency should have got changed... But, generally, frequency won't change for an object (correct me...

A pebble is dropped into a deep well, and 3.0s later the sound of a splash is heard as the pebble reaches the bottom of the well. The speed of sound in air is 340m/s. (A) How long does it take for the pebble to hit the water? (B) How long does it take for the sound to reach the observer? (C)...

I am building a moving target system for a shooting range. It will have a 40 foot target moving perpendicular to the shooter. I have not had any problem with fabricating the target system, but I want to go above what the customer requires. Hopefully this lead to more work for myself in the...

Homework Statement A policeman detects a drop of 10% in the pitch of the horn of a motor car as it crosses him. If the velocity of sound is 330ms^-1, calculate the speed of the car. Homework Equations f2 = f1 [v - v(listener)]/[v - v(source)] where f2 = apparent frequency f1 =...

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...

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