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.
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...
1. For this question, I need to explain why sound waves emitted into ocean water sometimes fail to give accurate results.
2.I have thought about, the salt density and the waves traveling through different water temperatures, but need to expand on these two ideas and don't understand it enough to...
Light waves, photons; sound waves, phonons; water waves, "hydrons"?
Light waves are made of photons; sound waves are made of phonons; so are water waves made of "hydrons", and if so, how would they behave, and would it be possible to make a water laser or something similar based on these particles.
Okay, I have this problem worked out, but I have no clue if my answers are right. Could someone please check my work and give me some confidence or show me where I may have messed up.
Homework Statement
Two loudspeakers, one of them generates sound with 400 W power the other with 100 W. The...
1-why does sound intensity increase at night?
2-what makes diffraction of sound more observable than diffraction of light?
3-reflection of sound takes place when it falls on a reflecting surface whatever the distance between the vibrating source and the surface
but in case of echo there are...
Postulate a parcel of air that is transmitting sound waves. Can that parcel ever be considered to be in a state of equilibrium? I maintain that it cannot. How say you?
I noticed that in water, sound travels faster than in air, but when light hits water, its velocity decreases.
Is this because sound is a longitudinal wave and light is a transverse (electromagnetic) wave??
Hello everybody,
I'd really like to be able to explain what I hear in terms of wavelengths. My question could be split into a few, but I will try to focus on the main issue so it's more simple to answer.
Situations in real life:
It comes to my mind when I'm in live shows, the loud ones...
I've encountered a bit of a conceptual problem in my studies and I was hoping someone could help me out with this:
I understand that the longitudinal sound wave takes the form of the equation s(x,t) = smcos(kx +/- wt), and that the equation for pressure variance produced by the sound wave...
i have a question about sound waves :
we know that the equation of sound wave can be written in the form s=Sm cos(kx-wt)
,but i still don't get the meaning of Sm .I know that in the transverse wave ingeneral , and in particular the string the maximum amplitude is how much the string can go...
Yes, I realize this may not seem like a very smart question but allow me to give some background.
I rent a room from a man in his 60s, let's call him Mr L. Mr L studied Pure Mathematics at university and was busy with his postgrad work when he suffered a schizophrenic breakdown. Because of...
(b) The frequency of sound waves received by a detector when both source and detector move
relative to the air is:
f=f0[u(+ or -)vd/u(+ or -)vs] . Two trains are approaching each other at a level
crossing and blow their whistles at a frequency of 500 Hz. Train 1 is traveling at 20% of the...
Homework Statement
two sound waves of the same frequency have respective amplitudes of 3 units and 1 unit and are traveling in opposite directions in the same straight line.At a particular place in that line ,the resultant wave will vary in loudness.The ratio maximum loudness/minimum loudness...
Today in my high school physics class, we were shown that object 1 vibrating at object 2's natural frequency, can cause object 2 to vibrate. So since you are transferring energy, i was wondering if its possible to use ultrasonic or infrasonic sound waves to vibrate a magnet, causing a current to...
Hey guys i have a question for my lab report that i can't solve. We did a lab where we had a pipe and produced sound resonance in there, using a generator to vary the frequencies and we recorded our data.
the general formula is for the closed pipe, fn= n (v/4L) and wavelenght= 4L/n.
The...
Homework Statement
I read that when a body approaches a stationary one which emits radar waves, the wavelength λ2 of the returned waves is longer than λ1, the wavelength of the emitted ones, but I get the opposite. I suppose this is true for sound waves also.
See picture.
The Attempt at a...
Sound waves, like light waves, can interfere w/ each other, giving max and min levels of sound. Suppose a listener standing directly between 2 loudspeakers hears the same tone being emitted from both. This listener observes that when one of the speakers is moved 0.16 m farther away, the...
Homework Statement
The two speakers are producing identical sound waves. The solid lines represent constructive interference regions and the dashed lines represent destructive interference regions. The point labeled 4 is 1228.5 m from the bottom speaker and 1618.5 m from the top speaker...
After watching the video below, I came up with the idea of using a piece of paper as a keyboard much like Mistry did for a mouse. I am only in high school, but I'm sure you can measure position via sine waves which relates to the sin trig function (the reason I posted here; if wrong thread, mods...
Hi Everyone,
Currently I am studying Stationary Waves and the relationships between the standing wave pattern for a given harmonic and the length-wavelength relationships for open end air columns.
I came across a statement that says that there is a relationship between temperature and sound...
Homework Statement
When the two microphones are at the same distance from the speaker, the two signals are in phase. For the phase difference shown (the two waves are separated by .001ms) , and given your value for the speed of sound(330m/s) , what is the minimum distance between the two...
Homework Statement
Show that the intensity of a sound wave passing through air is given by the equation I=1/2ρvω²A², where ρ is the density of air.
Assuming that the minimum sound intensity which a human ear can detect is 10-12W/m² at a frequency of 1kHz, calculate the amplitude and...
[b]1. A stationary research ship uses sonar to send a 1.18 × 103-hertz sound wave down
through the ocean water. The reflected sound wave from the flat ocean bottom 324 meters
below the ship is detected 0.425 second after it was sent from the ship.
a. Calculate the speed of the sound wave in...
Homework Statement
A bat emits a chirping sounds of frequency 67 kHz while hunting for moths to eat. Suppose the bat emits a chirp that lasts for 1.00 ms adn then is silent while it listens for the echo. If the beginning of the echo returns just after the outgoing chirp is finished, how...
Homework Statement
A loudspeaker at the origin emits sound waves on a day when the speed of sound is 340 m/s. A crest of the wave simultaneously passes listeners at the{xy} coordinates (43 ,0) and (0,33).What are the lowest two possible frequencies of the sound?
Homework Equations
v(sound)=...
What causes sound waves to be solely longitudinal in gas, liquid, and plasmas, but enables longitudinal and transverse in solids? Also, does solids only mean crystalline structures or are amorphous materials also able to support transverse sound waves?
1. As the sound wave propagates away from the source, the energy is "thermally eaten". So, there is a gradual decrease in kinetic energy of the vibrating particles. Doesn't that lower the frequency of the sound wave? (i first considered from the classical energy point of view and then wondered...
Sorry if this is a no-brainer, but I just can't seem to find much info about this.. All sources only talk about a single wave, most often a sinusoidal wave, and never mentions how the situation is like when there is a complicated sound signal with lots of stuff going on (different timbres for...
Homework Statement
Consider a sound wave in air of density 1.2 kg/m3. The displacement wave has the form s(x,t)=smaxcos(kx-\omegat) where k=8.79rad/m, \omega=3021.6 rad/s and smax=2.51 x 10-7m.
Calculate the sound pressure \DeltaP(x,t) of this wave at x=0.282m and t=0.00137s. Answer in units...
In an argument of sorts with another college classmate, please help. We were argueing science and religion. She stated that all life is made up of atoms, and atoms are now shown to be made up of soundwaves also. Not possible correct?
What if I put a light object like a small paper boat in front of a large subwoofer and a loud sine wave was played, will that object move away from the sub woofer?
Will the paper boat move away too if the above experiment was done in microgravity? The purpose of microgravity experiment is to...
1. You are standing some distance from a jackhammer where the sound intensity is bearable. You then walk half the distance toward the jackhammer. The change in sound level is about:
The given answer is 6dB.
I am not sure if this problem requires knowing what intensity "bearable"...
Homework Statement
I am confused with why the author uses this form for periodic sound waves.
Why did he use cosine instead?
Later, he states
Note he uses sin this time.
I know that the difference between sine and cosine is the phase offset, by 90 degrees.
But why did the...
I,ve noticed that when I fire a rifle that my left ear feels the most damage were my right ear feels allmost no damage. How can that be when my right ear is closest to the rifle chamber? I am right-handed.
I am extremely confused when it comes to particle-wave duality outside of the electromagnetic spectrum and quantum world. Are sound waves strictly waves or do they have "particle"-like aspects?
I understand that every particle has its own wave. Does this apply to every wave having a...
Homework Statement
A firework charge is detonated many meters above the ground. At a distance of 400m 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...
Homework Statement
A cowboy stands on horizontal ground between two parallel vertical cliffs. He is not midway between the cliffs. He fires a shot and hears it echoes. The second echo arrives 1.92s after the first and 1.47s before the third. Consider only the sound traveling parallel to the...
A block with a speaker bolted to it is connected to a spring having spring constant k= 20.0 N/m as in Figure P17.40. The total mass of the block and speaker is 5.00 kg, and the amplitude of this unit's motion is 0.500 m. (a) If the speaker emits sound waves of frequency 440 Hz, determine the...
Homework Statement
(1) A sound wave is traveling through air medium, if the medium is replaced by water, how that will affect the wavelength, frequency and speed of the wave ?
(2) If the temperature of the air changed, how that will affect the wavelength, frequency and speed of the wave ...
I have to draw frequency on an open and closed pipe. The top horizontal row is open organ pipe and the second horizontal row is a closed pipe. I have draw the frequency of sound on these but the open entrance of the sound is what is confusing me. Are these correct?
Homework Statement
Standing sound waves are produced in a pipe that is 1.60 {\rm m} long. 1) the pipe is closed at the left end and open at the right end , determine the locations along the pipe (measured from the left end) of the displacement nodes for the first overtone. 2) If the pipe is...
[b]1. You perform an experiment with a long column of air and a tuning fork. The column of air is defined by a very long vertical plastic tube with a circular cross section; the upper end of the tube is open to the outside air and the lower end of the tube is filled with water. The column of air...
Homework Statement
Two loudspeakers emit sound waves along the x-axis. A listener in front of both speakers hears a maximum sound intensity when speaker 2 is at the origin and speaker 1 is at x= 0.540 m. If speaker 1 is slowly moved forward, the sound intensity decreases and then...
Homework Statement
a stationary sound wave has a series of nodes. The distance between the first and the sixth node is 30.0 cm. What is the wavelength of the sound waves?
Homework Equations
The Attempt at a Solution
well no idea about it
but in my attempt to solve it, i tried...
Consider two loudspeakers (emitting sound waves of the same amplitude and wavelength of 15m) and an observer located in the x−y plane, with the two loudspeakers being at (2m, 0) and (−2m, 0), respectively, and the observer being at (0, 3m) initially.
(i) Suppose the intensity of the combined...
Refraction of sound is a term that refers to the fact that...
A. sound bounces off a smooth surface just as light bounces off a mirror.
B. different parts of a wave front travel at different speeds.
C. different frequencies of sound waves travel at different speeds.
D. sound waves only...