What is Sound waves: Definition and 332 Discussions
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid.
In human physiology and psychology, sound is the reception of such waves and their perception by the brain. Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (56 ft) to 1.7 centimetres (0.67 in). Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges.
Homework Statement
A jet is flying horizontally from A to B. When the plane is directly overhead at B, a person on the ground (C) hears the sound coming from A. ABC is a right triangle in B. The angle BCA = 36 degrees.
The average temperature is 20 degrees Celsius. If the speed of the plane...
Homework Statement
A tuning fork is set up near the end of an air filled tube(open at both ends) of variable length. By changing the length various position of maximum loudness( resonances) can be found. The difference in tube length between adjacent maxima is found to be 10.0 cm
a) wavelength...
A sound wave can be interpreted in any of four ways. Two of those involve the correspondence between (1)displacement and position and (2)pressure and position.
[By "position" here I refer to the distance from the source. Positive refers to going away from the source.]
These waves are 90...
Hey, i never quite knew where to post this so hope its okay here.
can sound waves specifically ultrasound around the 25 kHz mark be directed sort of how a laser pen directs light.
thanks.
Homework Statement
A sound wave with intensity 4 mW/m2 interferes destructively with a sound wave that has an intensity of 10 mW/m2. What is the intensity of the superposition of the two?
Homework Equations
sqrt of both values
The Attempt at a Solution
i believe that taking the...
Homework Statement
The intensity of the sound from a certain source is measured by two observers located at different positions along a line from the source. The observers are located on the same side of the source and are separated by 77.7 m. The observer that is closest to the source hears...
Homework Statement
An alarm clock has been thrown down a well.
around 100m deep well
an alarm clock with a frequency of 368hz sounds for 3 seconds
accelerating at 9.8 m/s2
initial velocity 0
Homework Equations
How deep is the well? using doppler
take in consideration of the echo...
I've been thinking, what sort of effects would changing the dimensions of a solid, (lets say a block of wood, or plank.) have on the sound waves passing through it.
For example, let's say I take a block of wood, and reduce the mass and surface area (I.E cutting the ends off a plank)? or cut...
Homework Statement
Two tuning forks 384Hz and 256Hz.
The question asks - would the sound of the combined frequencies be more similar to the 256 or 384Hz tuning fork. Estimate the frequency of the complex wave (noting that the pattern is repeated over three times).
We are given two...
Hey guys, I'm kinda having some problem with this question on finding the frequency of the sound wave of the picture provided. The speed the sound wave is traveling at is 340m/s. I know that in order to find the frequency, I hve to tke speed / wavelength. However, I'm not sure how to find the...
First of all does voice recognition rely on sound waves we create?
Second of all, is there any research that shows they relate and how voice recognition uses the sound waves?
Thanks
Hopefully i am not wasting anyones time, as i don't know a lot about sound waves etc.. but i was wondering if anyone could help. Is there such a thing that receives sound waves of around 1100hz. maybe a sound receiver and emmitter? I have tried finding as much infomation online, but there is...
Homework Statement
Ships measure the distance to the ocean bottom with sonar. A pulse of sound waves is aimed at the ocean bottom, then sensitive microphones listen for the echo. The graph shows the delay time as a function of the ship's position as it crosses 60 km of ocean.
Draw a...
1.Calculate the fundamental frequency of a steel rod of length 2.00 m. What is the next possible standing wave frequency of this rod? Where should the rod be clamped to excite a standing wave of this frequency?
first, i used the formula velocity of sound in the rod v=sqrt(Y/p)
where...
1.) A transverse wave is traveling with a speed of 300m/s on a horizontal string. If the tension in the string is increased by a factor of four, what is the speed of the wave?
2.) A wire has a cross-sectional area of 4.2 X 10-8 m2 and is made from a material whose density is 7900 kg/m3...
Homework Statement
People put their ears to a railroad track to get an early warning of an approaching train. why did this work.
Homework Equations
written response.
The Attempt at a Solution
Sound waves can travel a long way along an undisturbed metal rod?
Greetings!
Once again I don't know where to classify this tread... sorry.
My Question is the following:
Let's say we have a ball of mass, m. Let the mass be a steal ball for example.
We throw the ball at the floor. The impact that follows surely is a non-conservative impact.
(I hope I said...
Hi, I have been staring at this problem for 2 hours now, and I feel like it is really simple, but I cannot quite wrap my head around it...here it is
A violinist places her finger so that the vibrating section of her 1.0 g/m string has a length of 30 cm, then she draws her bow across it. A...
Homework Statement
When you drop a rock into a well, you hear the splash 1.5 sec later. How deep is the well?
Homework Equations
The Attempt at a Solution
Speed of sound 343m/s
x=(343m/s)(1.5)=514.5
Homework Statement
In a science fiction movie, when a spaceship explodes, the vibrations from the sound nearly destroy a nearby spaceship. If you were the science consultant for the movie, what would your advice be for the producer?
Homework Equations
I don't think there are any...
Homework Statement
Explain why different instruments produce sounds of different quality.
Homework Equations
None.
The Attempt at a Solution
Different instruments produce sounds of different quality as they produce sound waves with different waveforms.
-----------------------...
Homework Statement
Compare sound waves to waves in coaxial cables a.k.a. T.E.M.
I really have no idea how to answer this question. I've been researching and researching, and so far i can't find any information about WAVES for coaxial cables. Any help?
Thanks.
Homework Equations...
hey
i need to know how to find the temperature of a room using the speed of the sound waves.
if two rocks are hit together and then each strike is in time with the echo (rocks are 100m away from wall), and the time to make 150 strikes is 92 seconds, what is the air temperature?
thanks
Homework Statement
Here's the link for the questions: http://i13.photobucket.com/albums/a283/nadinevictor/PHYSICShw.jpg
There are quite a many.
Homework Equations
Speed of wave propagation= wavelength/period
The Attempt at a Solution
Homework Statement
Link to problem: http://img147.imageshack.us/my.php?image=soundqj3.png
Homework Equations
No idea, One of the reasons I'm asking. >.>
The Attempt at a Solution
Ok, I have no idea how to even begin this problem. I need a hint in the right direction, or just what...
Homework Statement
Diffraction occurs for all types of waves, including sound waves. High-frequency sound from a distant source with wavelength 9.20 cm passes through a narrow slit 11.5 cm wide. A microphone is placed 35.0 cm directly in front of the center of the slit. The microphone is then...
Homework Statement
Imagine you are in an open field where two loudspeakers are set up and connected to the same amplifier so that they emit sound waves in phase at 688 Hz. Take the speed of sound in air to be 344 m/s.
What is the shortest distance d you need to walk forward to be at a point...
Homework Statement
Earthquakes are essentially sound waves traveling through the earth. They are called seismic waves. Because the Earth is solid, it can support both longitudinal and transverse seismic waves. These travel at different speeds. The speed of longitudinal waves, called P waves...
Homework Statement
A 2.40 kHz sound wave is transmitted through an aluminum rod.
A) What is its wavelength in the aluminum?
B What is the sound wave's frequency when it passes into the air?
C) What is its wavelength in air?
The speed of sound in aluminum is 5100 m/s according to the...
A firework charge is detonated many meters above the ground. At a distance of 400 m from the explosion, the acoustic pressure reaches a maximum of 10.0 N/m2. Assume that the speed of sound is constant at 343 m/s throughout the atmosphere over the region considered, that the ground absorbs all...
Homework Statement
Two speakers are driven by the same oscillator whose frequency is 140 Hz. They are located on a vertical pole a distance of 4.45 m apart from each other. A man walks straight toward the lower speaker in a direction perpendicular to the pole.
(a) How many times will he hear...
Apparently, by what I read, the pressure intervals are 90 degrees out of phase with the displacement intervals for a sound wave. How is that so? When the medium is compressed, shouldn't the pressure be at a maximum and when at rarefactions, shouldn't the pressure be at a minimum?
Homework Statement
see topic title
Homework Equations
I think that sound waves are vibrations of particles in a medium. The vibrations continue until the energy is gone. Sound seems to need a medium to travel through.
Light can travel in a vacuum. your eye sees it from a source...
do sound waves carry momentum? any momentum at all (no matter how small)?
the obvious answer is that they carry energy but not momentum but i am wondering whether they don't theoretically carry some very tiny (usually negligible) amount of momentum in the same way that light, even though it...
Homework Statement
A tuning fork vibrating at 512 hertz falls from rest and accelerates at 9.81 m/s^2. How far below the point of release is the tuning fork when waves of frequency 485 Hz reach the release point? take the speed of sound in air to be 340 m/s. (don't forget it takes the sound...
Hello to all,
I've been wondering about sound waves for a while, and here's one question that came up...
Is there a natural limit to sounds being in the audible range... I mean, if we amplify the sounds (edit: the air pressure differences , since I'm not sure they would fall in the sound...
When sound waves of the same frequency interact, they amplify. Sound waves of different frequencies cancel each other out. Where does the energy go when they cancel?
The problem:
Two speakers emit a sound with a frequency of 550.0Hz. At what distance should they be placed to maximize destructive interference?
I have the steps in solving this problem written on my worksheet, and it says that the speakers should be placed at 1/2 wavelength. The thing I...
[SOLVED] Standing Sound Waves
What are the three longest wavelengths for standing sound waves in a 121 cm long tube that is (a) open at both ends and (b) open at one end, closed at the other?
the wavelength equation that i used for open-open was \lambda= 2L/m; where m is the number of...
Homework Statement
Two loudspeakers are located 3.42m apart on an outdoor stage. A listener is 18.80m from one and 19.60m from the other. During the sound check, a signal generator drives the two speakers in phase with the same amplitude and frequency. The transmitted frequency is swept...
Ok this problem seems blatantly easy but for some reason I just cannot find the equation.
Homework Statement
The middle C string of a piano is supposed to vibrate at 261.6 Hz when excited in its fundamental mode. A piano tuner finds that in a piano that has a tension of 900N on this...
[SOLVED] Sound waves and vibrations
I read a post here on PF dated back in Nov 2003.
'Security' needed some help with his Physics exam... and what a coincidence! I'm also working on that same exam now.
PF Admin 'chroot' helped him with the questions...
and I got confused with some of his...
"If two flutists play ther instuments together at the same intensity, is the sound twice as loud as that of either flutist playing alone at the intensity? Why or why not?"
I know that the answer has something to do with the sensation of loudness being logarithmic in the human ear, but I...
Homework Statement
The intensity at a distance of 6.0m from a source that is radiating equally in all directions is 6.0x10^-10 W/m^2. What is the power emitted by the source?
They give you multiple choice answers, and the answer is 2.7x10-7 W.
Homework Equations
I is...
[SOLVED] Sound waves in solids?
Hello!
As far as i have learned sound waves are longitudinal! They propagate in gases liquids and plasmas. Does sound waves propagate through solids too? If so, what type of waves? Longitudinal or transversal?
Thanks
Note:If you consider this homework, sorry...
Homework Statement
(a) Standing sound waves are produced in a pipe that is 2.00 m long and open at both ends. (Give all answers measured from the left end of the pipe, and from smallest to largest where there is more than one answer.)
(i) For the fundamental and first two overtones...
Homework Statement
The speed of sound along the ground is about 6.75 km/s while the speed of sound in air is 342 m/s. A very powerful explosion occurs some distance away and you feel the ground vibrate 74.0 seconds before you hear the sound of the explosion. How far away is the explosion...
The topic came up the other day in class, about how the wave frequencies vary in each pipe of an organ. I am looking for some comprehensive information on the topic, and it would be great if someone could direct me, or maybe help a little bit as I am not so sure, as we haven't covered the topic...