Doppler Definition and 713 Threads

doppler effect / expanding universe . trouble uniting both concepts? Ok, I think I understand both; I just don't understand their relationship. As I understand the doppler effect, in short, its cause by the difference in velocity (movement through space). And as I understand the expansion...

I am playing with a small personal fan and I noticed that when the blades are moving at some frequency that "lines up" with my monitor refresh rate frequency, they appear blurry and stationary, but with altered shapes. Not only that, but certain edges of the blades are colored blue, while the...

A student runs toward the closed end of a hall while holding a vibrating tuning fork. The tuning fork is vibrating at 512Hz. The sound is reflected from the end of the hall back to the running student where 8.0 beats per second can be heard. Determind the speed of the student. i used the...

So the Red shift of extragalactic bodies means that they are moving away from us. And this effect is seen for all extra galactic objects minus the local group of galaxies. How then is it known that our local group is not the center of the universe? Wouldn't the fact that everything is moving...

Hi, I am a little confused about some aspects of sound waves. I was hoping to just check to see if I am on the right track. I have a problem where a guy is moving towards the great wall of china, with a air horn, emitting a constant frequency sound of 500Hz. The sounds is going to hit the...

I have a quick relativity question. Say an observer is moving at a relativistic velocity with respect to some light source that emits light at one particular frequency (the observer's path does not intersect the emitter). At the point of closest approach, will light from the emitter be Doppler...

Doppler effect homework problem help (still lost) Homework Statement A block with a speaker bolted to it is connected to a spring having spring constant k = 17.0 N/m, as in Figure P17.40. The total mass of the block and speaker is 44.00 kg, and the amplitude of this unit's motion is 0.475...

Homework Statement At the Indianapolis 500, you can measure the speed of cars just by listening to the difference in pitch of the engine noise between approaching and receding cars. Suppose the sound of a certain car drops by a factor of 1.50 as it goes by on the straightaway. How fast is it...

Homework Statement Is this true? the observed doppler shift for sound waves depends only on the relative motion of the source and the receiver. Homework Equations this is a concept-like question The Attempt at a Solution If no, doesn't mean, wind will affect the doppler effect?

Using a highly sensitive parabolic sound collector, Tom records the frequency of a tuning fork as it drops into the Grand Canyon. He drops the vibrating tuning fork from rest at t=0. He records a frequency of 1887.0 Hz at t=7.880 s. What is the natural frequency of the tuning fork? Use...

Assume: Take the speed of sound in air to be 343 m/s. A bat, moving at 5.9 m/s, is chasing a flying insect. The bat emits a 46 kHz chirp and receives back an echo at 46.26 kHz. At what speed is the bat gaining on its prey? Answer in units of m/s. I tried this: f=initial frequency...

Einstein in his "On the electrodynamics of moving bodies" (1905) starts the derivation of the Doppler shift formula by stating: In the system K, very far from the origin of coordinates let there be a sourcce of electromagnetic waves..." . Taking into account his advise "never stop thinking" we...

Hey guys...or ladies...um...just wondering what I hav done wrong for the following Q, it is an online Q i am doing and it tells me my answer is incorrect? Q) "A car alarm is emitting sound waves of frequency 520 Hz. You are on a motorcycle, traveling directly away from the car." "How...

In relativistic doppler shift, the energy of the photon is increasing och decreasing, due to realative motion of observer vs emitter. Let say that the photon is redshiftet, does any energy dissapear? :rolleyes:

I know that in spectroscopic Binaries, you can observe wavelength shifts in each star. But how do you determine the total radial velocity of this system alltogether, and how do you find each star's radial velocity?

Homework Statement Suppose that a police car on the highway is moving to the right at 28 m/s, while a speeder is coming up from almost directly behind at a speed of 34 m/s, both speeds being with respect to the ground. The police officer aims a radar gun at the speeder. Assume that the...

I was playing around with a thought experiment where an observer is moving towards a light source at a speed infinitesimally less than C and it seems like, for any given wavelength, the maximum possible Doppler shift is 1/2. for example near infrared light with a wavelength of 800 nm would be...

I have a question regarding the doppler effect and frequency: You (a stationary observer) are standing by the railroad tracks and hear a frequency of 1000 Hz as the train approaches... as the train goes away, the frequency changes to 800 Hz. Knowing that the speed of sound is 340 m/s, how...

A train is traveling at 30.0 m/s relative to the ground in still air. The frequency of the note emitted by the train whistle is 262 Hz. a. What frequency (fapproach) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first...

I would need a pointer to a mainstream treatment of the general relativistic Doppler effect when source and receiver are accelerated wrt each other. Book/paper/wiki . No crank papers , please (i.e. no Apeiron and such). Thank you.

I'm working through the derivation found on this site: http://maths.dur.ac.uk/~dma0cvj/mathphys/supplements/supplement5/supplement5.html And though most of it is clear to me, I stumbled upon a little problem. My question is about the section that starts with "This is all according to...

Homework Statement The hydrogen atoms in a star are also moving at high velocity because of the random motions caused by their high temperature. As a result, each atom is Doppler shifted a little bit differently, leading to a finite width of each spectral line, such as the 656.46-nm line we...

I have heard that if one is hypothetically placed in a box completely solid, whith a shield that leaves everything that would have entered a normal box, like light, or neutrinos, out of it. If you sent that in a certain speed, with nothing affecting it, just traversing through space, the person...

can someone pleasezz explain the dopplers effect n when to use the c-v0 , c+v0 ,c +Vs ,c-Vs etc etc in the formula in the pic thnx a lot in advance

I cannot search the forum to check if this has been posted before, because I do not know what it is called in english... That means that i have to try to explain what i means, here it goes: When a light producer, like a star is moving, it sends out waves that is either compressed or expanded...

Hello I have a question that is giving me trouble: Light of wavelength 659.7 nm is emitted by a star. The wavelength of this light as measured on Earth is 661.1 nm. How fast is the star moving with respect to Earth? km/s Is it moving toward Earth or away from it? Here's where...

I have to calculate the suns period time, when given the following information; "The H_{alpha} line has the wavelength \lambda_0 = 656.1~nm . Measuring this spectrum from opposite sites of the suns equator, shows that there is a difference between that is \Delta \lambda=9\times 10^{-12}~m ...

Hello, The reason for the shifting of freqeuncies of all types of waves in response to relative motion away or towards the center of propagation, is caused by a corresponding stretching or compressing of the medium, correct? I mean for sound, if one moves toward the place where the sound...

Here's a problem that's been bugging me. We know that we get sonic booms because of the Doppler effect since, for an example, the jetplane over takes the soundwaves that it emits some time ago because it is travels faster than the speed of sound. The overlapping of new sound waves it produce...

defining the Doppler Effect as: "what we have to compare in a Doppler effect experiment are the period at which light signals are emitted measured in the rest frame of the source and the period at which they are received by an observer measured in its rest frame" we are doing a good job...

Question: An ambulance with a siren emitting a whine at 1300 Hz overtakes and passes a cyclist pedaling a bike at 2.44 m/s. After being passed, the cyclist hears a frequency of 1280 Hz. Use 343 m/s for the speed of sound in air. How fast is the ambulance moving? i set up the doppler equation...

Please help me: . While standing at a crosswalk, you hear a frequency of 630 Hz from an approaching police car. After the police car passes, its frequency is 430 Hz. What is the velocity of the police car? (speed of sound in air = 343 m/s)

Hi - I'll keep this relatively short. I'm doing an investigation into the doppler effect and I need to do a series of 3 to 5 experiments in order to prove/show something. At the moment I am a little lost as to what I could experiment into regarding the doppler effect, and how to go about it in...

A friend and class-fellow of mine(B.B. Gupta) came up with the following interesting problem(during the starting days of our M.Sc.):-There's a photocell and a (monochromatic)source of light at a certain distance from the photocell.The source of light emits light of frequency lower than what is...

For this problem, I used the Doppler Effect equation, and got 419.361 as my answer. I used + on the top and - on the bottom. Do I need to switch the two?

Im trying to find the ansewr to an extra credit question in class. We are studing the doppler effect and the question came up does wind effect the sound you hear. At first i was thinking that it might but since the velocity of sound is so much greater than that of wind that you would notice no...

A stationary source directs an 800-Hz sound wave toward an approaching object moving with a speed of 25.0 m/s. What is the frequency shift of the reflected wave if the air temperature is 20ºC? (Hint: There are two Doppler shifts here. Why?) f = 800Hz the speed of sound = v = 331 + 0.6Tc =...

"Is there a Doppler effect if a sound source and an object are moving at right angles?" I assume this means that both are moving away from a single point... I thought there would be a Doppler effect because both objects are moving and therefore the sound produced has an effective longer...

a motorcycle starts from rest and accelerates along a straight line at 2.81m/s^2. the speed of sound is 343 m/s. a siren at the starting point remains stationary. how far has the motorcycle gone when the drive hears the frequency of the siren at 90.0% of the value it has when the motorcycle is...

Hey guys, Im having lots of problems with this question.. A car moving at 40m/s and a truck moving at 15m/s travel along the same straight road. The car's horn has a natural frequency of 400Hz. What is the change in the frequency observed by the truck as the car passes the truck? Assume the...

This is the problem A shuttle is launched from a space station and travels away from it in a straight line. It rapidly accelerates and obtains a steady velocity of v = 4c/5 relative to the space station. The spaceship sends out radio signals of a frequency f. The spaceship is on a mission to...

I have a simple question about a relativistic Doppler effect problem. To keep the math simple, I have intentionally left out the labels, you can view the speed of light as 300 miles per seconds, or 300 meters per second, it isn’t important. Speed of light = 300 per second Wavelength of...

I had a question. I did a problem where a distant galaxy emitted light that had a wavelength of A. On earth, the light had a wavelength of B. B ended up being greater than A. The question asked if the galaxy was receding from the Earth or approaching the earth. The answer turned out to be the...

Is there somebody who knows the way in which aetgherists derive the formula that accounts for the optical Doppler effect?

Okay, I don't need an answer . . . I just need to know how I would go about getting an answer. Here is the question, exactly worded as on my worksheet: "What is the up-doppler for a 600.0 nanometer laser scanning an innocent, law-abiding, safe-driving, tax-paying, completely innocent...

I am doing an experiment in the lab at the moment on laser doppler anemometry and a few questions have popped into mind, was wondering if anyone had any ideas/insights on them: Direct detection of the Doppler frequency shift using conventional prism or grating spectrometers is not usually...

Why does the wavelength of the wave change when source is moving but not when listener moves?

Hi, A very hot gas is enclosed in an oven with a small window. The gas molecules emits radiation at a characteristic wavelength. I assume that because of the thermal motion of the molecules the emitted wavelengths will form a spectrum of some kind (Doppler broadening.) I am trying to derive...

Can i use the doppler formula ( i.e f = f(0){(v(+/-)v(0))/(v(+/-)v(s))}) when the source is accelerated taking v as the speed of sound in air v(o) the speed of the observer and v(s) the speed of source at the time the sound wave is generated . I tried deriving this formula but came across some...

1.) Suppose the sound from an approaching train whistle normally has a frequency of 1200 cycles per second, but the train is approaching at 50 meters per second. How would the Doppler Effect change the wavelength of the sound? (speed of sound 335 meters per second; I would like a quantitative...