Sound Definition and 1000 Threads

Consider a fixed sound of intensity level SIL1 = 70 dB and another (of different frequency) whose intensity level takes on the series of values SIL2 = 50, 60, 70, 80 and 90 dB. (a) To the nearest dB, what is the level of the combined sound in each case? (b) Make a general statement about the...

What is the nature of sound in each dimension e.d 1D, 2D, etc and how can one be differentiated from the other. I do not seek formulas just a straight forward explanation.

Homework Statement Given the tension T and unit mass per length U of a string what is the speed of sound along the string Homework Equations The Attempt at a Solution I know how to find the propagation speed of a transverse wave on a string, is that the same as the speed of...

Hi everyone! I have to do an experiment in the lab related with interference in sound waves with same frecuency. I am just looking for ideas or suggestions. Thanks!.

I want to define (and find the sound velocity i iron). can i read it through the dispersion curves of iron? I am trying to see it through the group propagation velocity, vg = dw/dk, i. e the slope of the dispersion relation w(k). am i on the right track? thanks

Homework Statement The questions states, "If you speak while standing in a corner with your face toward the wall, you will sometimes notice that your voice sounds unusually loud. Explain."The Attempt at a Solution Is this because the sound waves are bunched up when they bounce off the corner...

Problem: The problem asks to find which frequencies a listener, whom is receiving sound waves in the same direction from two variable-frequency speakers 50ft and 55ft away, will not hear anything at all. Solution (so far): My approach is to find an expression for the wave coming from each...

Rocket travels into space, emits sound -- intensity/time question Homework Statement A rocket, starting from rest, travels straight up with an acceleration of 56.7 m/s2. When the rocket is at a height of 722 m, it produces a sound that eventually reaches a ground-based monitoring station...

An archer fires an arrow, which produces a muffled "thwok" sound after it hits a target. If the archer hears the "thwok" exactly 3.0 s after firing the arrow and the average speed of the arrow was 33 m/s, what was the distance sepa*rating the archer and the target? Use 340 m/ s for the speed of...

Problem: In my physics class, we conducted an experiment involving a column of air set vibrating by a tuning fork of a known frequency f held at the upper end. The wave travels from the source to a fixed end (namely the water in the lower end of the tube) & reflected back to the source...

Homework Statement See: https://aapt.org/physicsteam/2012/upload/exam1-2011-1-3-answers_1.pdf Number 14 Homework Equations None that come to mind The Attempt at a Solution I think this is a conceptual question where each needs to be more proportionally spread apart because it...

The physics behind human whistling--where does the sound come from? In most whistles, air is split somehow. When humans whistle (by forming a small hole with their lips), this is definitely not the case. I would assume that the mouth is the resonance chamber because pitch can be altered by...

I'm just trying to get a better grasp on sound waves and shock waves. Let's say I have a cylindrical rod of length L with no forces acting on it, and I push on the back of it with some constant velocity less than the speed of sound, c, of the material the rod is made of. Will the front of the...

Homework Statement Hey guys, I'm having a hard time understanding this whole waves chapter and my teacher just gave us a tricky problem... So you have a single slit and it accommodates 3-6 wave lengths across its diameter. Assume that the sound created when echoing off objects may be...

My textbook says that in the equation β= 10log(I1/I2), I1 in most cases is the threshold of hearing (1.0x10^-12). Just out of curiosity, when is I1 not the threshold of hearing?

Hello there I love physics, so I normally read a lot of physics books. I am fascinated about BECs and their possible applications. I've read about BECs and BEC vacuum theory, also that is possible to create black holes in superfluids (as BEC) using sound (sonic black holes). As far as I know...

Homework Statement You are standing on the side of the Trans-Canada Highway as the Physicsmobile approaches you. As it approaches, you hear an engine noise of 1100 Hz. After it passes, you hear an engine noise of 950 Hz. How fast was the Physicsmobile travelling? Homework Equations...

Hello I have some questions regarding the following problem: Imagine I have a glass beaker partially filled with water. Assume that I were to hit the beaker (say at the top edge to be specific) with a noodle stick. Assume that I do not hit again until the vibrations have completely died...

Homework Statement The sound from a trumpet radiates uniformly in all directions in air with a temperature of 20 degC. At a distance of 4.80m from the trumpet, the sound intensity level is 47.0dB. The frequency is 576Hz. Also knowing speed of sound in air is 344m/s, the density is 1.20kg/m^3...

PIC (A) http://imageshack.us/a/img37/941/img20130104192537.th.jpg PIC (B) http://imageshack.us/a/img23/5496/img20130104192554.th.jpg I hope you can ans it in a simple way as I am just a secondary 6 student :) thx! For pic a, 1. I dun understand why interference occurs when there is 1 slit...

The title basically says it all, I'm wondering whether dark matter will allow sound to pass through because if it does, that could lead to being a way how to detect dark matter.

Was just wondering whether or not it was at all possible to create "sound" from molecule interactions, and if so how would I go about it? I was going on the theory that if E=hv then a frequency is obtained when this equation is applied and as sound is theoretically a frequency (movement of...

Hello! We are trying to verify if an acoustic standing wave has been established in a cavity. In order to do so, we are giving a constant frequency signal to a speaker. We are picking up the signal at two locations, one very close to the speaker(reference signal) and at a particular...

Homework Statement David is swimming when he hears a beaver sap the water with its tail, first through the water (v= 1400 meters/second) and then 0.95 seconds later (after the sound reaches him through the water) through the air (v= 340 meters/second). Homework Equations Find the...

Homework Statement A car honks a 2kHz tone and is 40m from a long high wall. A man is running parallel to the wall, 10m away from it, at 5 m/s, and is presently 30m away from where the whistle is closest to the wall. How many beats/second will be heard by the runner as he will hear the direct...

I read on the 'Ask A Mathematician/Ask A Physicist' blog that sound waves behave differently in an even-number of dimensions than they do in odd-number dimensions - that they 'double-back'. Why is this - and what does 'double-back' mean...

I am in the process of building a piezoelectric device to harvest sound with a frequency generator at one side of a plastic/glass tube which sends out a low frequency which is then picked up by a piezo disk which send the energy to an led which demonstrates hoe sound can be converted to...

Homework Statement Homework Equations The equation that is already given + (maybe) I is proportional to A2f2. The Attempt at a Solution I took the square root of 8, 8 being the Amplitude and I being proportional to the square of A. (I make the constant of proportionality 1)...

A swimmer sees a parachutist hit the water and hears the impact twice, once through the water and the second time through the air, 1.0 s later. How far from the swimmer did the impact occur? Vs air = 340 m/s Vs water = 1400 m/s the answer is 450m I don't understand what to do...

A tuning fork vibrates 235 times in 3.1 seconds with an amplitude of 0.59mm. Determine.. i) its frequency ii) its period iii) the distance the end of one of the fork tines travels in one second for i) The answer I got is f=75.81Hz ii) The answer I got is 0.13s iii) ?

first of all sorry for my bad english. i know i need to improve it :) now, let's talk aobout my question. You know there is a few ways to block sound indoor with sponge or some materials. i searched on internet but i coulndt find anything to block sound outdoor. i have a project and i need...

Homework Statement An observer listens to a vibrating string using a cardboard tube of length 1.4m placed close to his ear (one end closed). The string is excited so as to vibrate at its fundamental frequency, and the tension is increased slowly. The intensity of the sound heard by the...

I am trying to find a description of sound waves and speed of sound in gases using Kinetic Theory. I mean to derive the sound waves in a medium like gas , composed of molecules moving and colliding as Kinetic Theory describes. The origin of the sound wave, as our experience shows, is the...

Hi, my friends. Today, I come up with a question suddenly. It is about Sound diffraction. why can we hear someone's voice even when he is in a closed office. Many books says that it is because of Sound diffraction. But I can't understand. how does it happen? would you be so kind to explain it...

Homework Statement A 285Hz sound wave is directed into one end of a trombone slide A microphone is placed at the other end to record the intensity of sound waves that are transmitted through the tube. The straight sides of the slide are 80cm in length and 10cm apart with a semicircular bend...

Hi everyone, I have a sound wave representing a piano piece played at a steady tempo, and would like to get a graph of the saliency of each beat (essentially, a probability distribution for how strong each possible tempo is). I understand that this is done by plotting the autocorrelation...

I was reading an article on Acoustic Levitation http://science.howstuffworks.com/acoustic-levitation2.htm and near the end it said This got me thinking about the character Banshee from X-Men Who's power, as described by the X-Men wikia is Now I understand that this is not the same thing as...

Because obviously too much density gives terrible sound quality, like in water. So is the answer simply the density of our lower atmosphere because that is where our ears evolved? Or has this been tested and found to be a specific density?

I was thinking about refraction of waves and I´m a little unsure. I wanted to run my understanding through you guys to make sure I´m right. So The general rule is when a wave goes from a slower medium to a faster medium the wave should turn sligtly away from the faster medium when it...

Homework Statement You drop a stone down a well. You hear the 'splash' 1.63s later. How deep is the well? The speed of sound in air is 343m/s. Homework Equations Kinematic equation: Δh=V0t+1/2gt2 Also, I've narrowed the problem down to the total time of 1.63s is equal to... 1) the...

I have been researching about splitting water including electrolysis, but I came across about using ultrasonic sound wave to split water, I search around and it said that water will decompose at 42000 hertz, is this true, because I am going to do it for my project. May anyone please give me a...

Homework Statement http://img543.imageshack.us/img543/4598/photosfr.jpg Find dss, dsr and thus hs. Homework Equations trig The Attempt at a Solution dss = hs/(sin[θ]) dsr = hs/(sin[∅]) dss = 3.059/(cos[θ]) dsr = 47.191/(cos[∅]) θ = arctan(hs/3.059) ∅ = arctan(hs/47.191) I have tried...

What are the differences (I'm really trying to understand the differences in the context of an explosion). When you hear it, are you hearing all 4 waves? Which waves cause the damage and why - why not the others? Also, when NASA launches the space shuttle, they release water to absorb the...

Hey everybody, I'm trying to figure out what the vibration modes of a circular membrane would look like if we put some sound through it. As you may know does a circular membrane with clamped edges at radius a behave according to the wave equation. The general solution thereof has the form...

Homework Statement Suppose sound wave is emitted uniformly in all directions by a speaker. At a distance of 1.1m, the amplitude of it sound is 1.2x10^-8m What is the amplitude of sound at a distance of 1.7m?The Attempt at a Solution What I'm confused is why does the amplitude of sound change...

Doesn't Felix have an advantage when breaking the sound barrier since the air in which he is moving is less dense, therefore the speed of sound itself is considerably slower? (Felix Baumgartner is the man who recently jumped from 128,000 feet in an attempt to become the first man to break the...

Why doesen't hand swaying produce sound and why does my slight scratching my skin produce an audible sound?

Homework Statement Given that: TI1 + TI2 = 70 dB TI2 + TI3 = 80 dB Find TI1 + TI2 + TI3Homework Equations TI = 10 log (I/Io)The Attempt at a Solution From that two equations, I got: I1.I2 = 10-17 I2.I3 = 10-16 I1.I22.I3 = 10-33 Then stuck...

hello physicsforum. i came here hopefully someone can answer this. heres what happend: i was out suing my camping stove. after i turn it off, and start packing it away, i shone the flashlight onto it and that's when i first discovered that there is a buzzing sound coming from it...

Homework Statement A firework charge is detonated many metres above the ground. At a distance d1=550 m from the explosion, the acoustic pressure reaches a maximum of ΔPmax = 10 Pa. Assume the speed is constant at 343 m/s throughout the atmosphere over the region considered and the ground...