Doppler Definition and 713 Threads

Homework Statement The security alarm on a parked car goes off and produces a frequency of 958 Hz. The speed of sound is 343 m/s. As you drive toward this parked car, pass it, and drive away, you observe the frequency to change by 95 Hz. At what speed are you driving? Homework...

I have just read about the principle of Doppler effect. However there is a point which seemed a bit tricky. According to the book, when the source of wave is moving the apparent frequency to a stationary observer is given by the equation: f'=true frequency*speed of wave/(speed of wave +...

When we analyze the light coming from a distant galaxy, we find a particular absorption line with a wavelength of 1118 nm. This same absorption line in light from the sun has a wavelength of 625 nm is this galaxy moving towards us or away from us? Calculate the magnitude of the velocity of...

Homework Statement A stationary observer at a crosswalk hears an ambulance siren with an apparent frequency of 480 Hz when the ambulance is approaching. After the ambulance passes the apparent frequency is only 420 Hz. Find the speed of the ambulance. Assume v = 343 m/s for the speed of sound...

Homework Statement A doppler effect problem: A sodium atom is emitting radiation at a wavelength of 6000 angstroms. When measured however the wavelength is widened to 6000 +/- 0.02 angstams. If this is primarily due to the doppler effect, what is the temperature of the sodium atom...

Hi All, I would like to know how can one explain the assimmetry in Doppler effect. I will illustrate what I mean. If a source emits 440 Hz but is coming in my direction with a velocity V (measured in m/s) I will hear, let's say, 441 Hz. Now, if the source is at rest with respect to the...

Homework Statement In a distant galaxy, an emission line of hydrogen that has a rest wavelength of 656 nm has an observed wavelength of 662.6 nm. Is the galaxy moving away from us or toward us? How fast is it moving in (km/sec)? Homework Equations velocity = ((shifted wavelength -...

Homework Statement A source S and a detector D are initially at a distance of x=1km. Both start moving towards one another with same acceleration a = 10m/s2. Frequency of source is f = 2000Hz. Find the frequency observed by the detector at time t=4s. Speed of sound in air is v=300m/s The...

Hi. I am learning special Relativity and I am seeing that the answer to the twin paradox involves the Doppler effect, and I am struggling to understand what is going on. First let me explain what I know about the Doppler effect. If an object produces waves (might it be light waves or sound...

I'm doing a night course in General Relativity and we're currently finishing off Special Relativity... We're working mainly off of D'Inverno. We've just covered the relativistic doppler effect and some associated things like aberration. When it came to talking about the transverse doppler...

Imagine this scenario: An aeroplane emits a sound wave. The sound wave propagates in all directions. a) If the plane is flying forward, it emits a sound towards a reflector in front of it. When the sound is reflected, its frequency is reduced, presuming the plane is traveling towards the...

Does Doppler effect exhibit in sound waves, light waves and the waves on the surface of the water?

At page http://www.qsl.net/vk3jed/doppler.html" is discussed Doppler shift at various ham radio frequencies. I calculated for this Doppler shift relative velocity of their satellite as 6720 m/s. Their satellite in height of 800 km above ground and at circular orbit should have velocity of 7453...

Homework Statement A source and detector are placed a certain angle \phi apart on the edge of a rotating disk. The source emits radiation in all directions at a frequency \omega_* in its instantaneous rest frame. What frequency is the radiation detected at? (Hint: Little information is...

Hi, I'm interested in the derivation of the gravitational redshift formula from the Doppler shift in an accelerated frame formula (or viceversa), that are linked by the Equivalence principle, it should be pretty straightforward but I get stuck. Anyone can show me this or point me to a link with...

When we first realized that the further away a galaxy is the further towards the red side of the spectrum it was, we beleived this to be do to the expansion of the universe? Wouldn't it have been simplier to say that the further away a galaxy was the further the wave function stretched over...

Homework Statement A bat, flying at a constant speed of 19.5 m/s in a straight line toward a vertical cave wall, makes a single clicking noise and hears the echo 0.15 s later. Assuming that she continued flying at her original speed, how close was she to the wall when she received the echo...

Did u ever try to explain Doppler effect for light in depth, at the photon level ? I'm no scientist. I'm trying to find a visual or mental representation of the doppler effect for electromagnetic waves. There is no medium to vibrate. No way I can understand the phenomenon by making a...

I've been trying to graph an idea I had, but frankly I don't understand SR well enough to ensure my assumptions are correct, and that I'm using the correct formulas. I would appreciate any input/corrections you folks could give. Here's the idea, which I'll follow with my assumptions: Idea...

is the light doppler effect a purely relativistic effect? or it is present even in the classical limit?

Homework Statement A car is getting closer to a radar as a speed of 135 km/h. If the radar works at a 2 \times 10 ^{9} Hz, what difference of frequency is observed for the radar?Homework Equations \mu=\frac{\mu _0 \sqrt {1- \frac{v^2}{c^2}}}{1-\frac{v}{c}}The Attempt at a Solution I converted...

I know that photons hitting a solar sail can add energy to that sail. I know that photons are gauge bosons. I know that gauge bosons are thought to be the carriers of fundamental forces. If a solar sail were gaining speed to a point where it reached relativistically with respect to the power...

Problem: Three radio-equipped plumbing vans are broadcasting on the same frequency,f0. Van 1 is moving north of van 2 with speed v, van 2 is fixed, and van 3 is moving west of van 2 with speed v. what change in frequency (f-f0) does van 3 hear from van 2? From van 1? Attempt at solution...

Homework Statement Firstly, whilst reading all this more complicated (and far more interesting) physics in other threads I feel like a dunce posting something which is probably of 'lower' level here as it were, but here goes: If we have a vehicle like a police car (with siren going) moving at...

We observe farther galaxies with higher redshifts. How can we be sure that this is due space itself expanding? How do we know that this is not just Doppler shift of galaxies running away from us at higher speeds long time ago, that got lowered (decelerated by gravity of matter in the...

I have always been taught, that we can tell how fast a galaxy is moving away from us by it's amount of doppler shift. If the atoms in the stars of those galaxies are moving very fast (i.e. that galaxy is moving faster than our galaxy is moving), relativity would have a bigger effect on them...

Homework Statement An automobile is approaching you at a speed of 60.0 km/h and sounding its horn. The fundamental frequency of the horn sounds to you like 388 Hz. If the real fundamental frequency of the horn is 369 Hz, what is the speed of sound? Homework Equations Doppler...

Will gravity waves theoretically experience a doppler effect for bodies in relative motion to the source?

Homework Statement An ambulance is traveling at 84.0 km/h. The ambulance has a siren which produces sound at a frequency of 1.7 kHz. Assume the speed of sound in air is 345.0 m/s. A police car is traveling at a constant speed of 80.0 km/h directly towards the ambulance. The police car...

Homework Statement An ambulance is traveling at 72.0 km/h towards an intersection. Jim stops his car to give way to the ambulance as shown in the diagram below. In the diagram, the angle θ = 41.0 °. The ambulance has a siren which produces sound at a frequency of 2.1 kHz. Assume the speed...

Homework Statement A car is traveling at 30m/s in still air. the frequency of the siren on the car is 600hz. The velocity of sound in still air is 330 m/s. what is the wavelength of the sound waves a)directly in front of the car b)directly behind the car What is the frequency of the...

Homework Statement A French and a U.S. submarine are moving directly towards each other during manoeuvres in still water. The French submarine is moving at 50.0 km.hr-1. It sends out a sonar signal at 1100.0 Hz. The frequency detected by the French submarine (reflected back from the U.S...

Homework Statement A French and a U.S. submarine are moving directly towards each other during manoeuvres in still water. The French submarine is moving at 50.0 km.hr-1. It sends out a sonar signal at 1100.0 Hz. The frequency detected by the French submarine (reflected back from the U.S...

Homework Statement A stuntwoman is preparing to take a punch, crash through a "candy glass" window, and fall a long distance. The script calls for her to emit a piercing scream just before she hits the "ground." In reality, she will land on a waiting airbag. Lights! Camera! Action! The...

If as a result of the equivalence principle we can derive the gravitational red shift entirely from the perspective of an accelerating body with no reference to gravity and no reference to gravitational time dilation then one is essentially just working out the Doppler shift of a signal...

I am a bit confused here. Is cosmological redshift the same as doppler redshift? This is from wikipedia: "The redshift z often is described as a redshift velocity, which is the recessional velocity that would produce the same redshift if it were caused by a linear Doppler effect (which...

A police car's siren emits a wave with a frequency of 60 Hz. The speed of sound is 300 m/s and the car is moving 50 m/s. "what is the wavelength of the wave behind the car" So, the answer seems pretty easy. The observer is a stationary point behind the car, and the source is moving away...

Doppler effect and Resonance--relationship? we have a structure called Menar Jonban (i.e. Shaking Minaret-- it's basically a minaret that could be shaken --- literally!..you shake one minaret and the other one shakes too!) ... obviously the best explanation of the phenomenon is resonance .. but...

In several threads where I've seen the redshift issue discussed there's been some confusion about this point, Must we treat cosmological redshift as a purely kinematic (relativistic)doppler effect or as the time dymamics of the metric space? Or both views can be made to converge?

Homework Statement -You are traveling in a car near a speeding train. The train whistle blows but you fail to hear the doppler effect. What conditions might prevent you from hearing it? Homework Equations The Attempt at a Solution -Ok, all I can come up with is that maybe...

Homework Statement The sound source of a ship's sonar system operates at a frequency of 23.0 kHz. The speed of sound in water is 1482 m/s. What is the difference in frequency between the directly radiated waves and the waves reflected from a whale traveling straight toward the ship at...

Hey all, I'm a newbie here with a question regarding doppler shift. Before I ask, I only have a very basic understanding of the doppler effect. So, my big question is: can a doppler shift measurement be converted to the distance between the source and target, without using the time of...

Hii guys.I have this problem.Can anybody help me on this.tq Homework Statement A satellite is in a circular polar orbit at a height of 870 km, the orbital period being approximately 102 min. The satellite orbit passes directly over a beacon at sea level. Assuming an average value of...

Doppler shift with microwaves...i think... Homework Statement Microwaves, which travel at the speed of light, are reflected from a distant airplane approaching the microwave source. It is found that when the reflected waves are beat against the waves radiating from the source, the beat...

Homework Statement A bus is moving at 37.00m/s towards a wall. The sound from the bus has an original wavelength of 0.1500m. The sound from the bus reflects off the wall. What frequency sound does an observer on the moving bus hear from the reflection?? Homework Equations Moving Observer: fo...

I need the following statements logically-'spellchecked'. The internet, nor books will put it this simply, so I typed up what I feel is a summary, but I don't want to be incorrect in my own mind by doing so. So please proof read my logic and correct it for errors: The doppler effect IS...

Homework Statement a. A fire engine is moving at 40 m/s and sounding its horns. A car in front of the fire engine is moving at 30 m/s, and a van in front of the car is stationary. Which observer hears the fire engine's horn at higher pitch, the driver of the car or the van? b. A bat flying...

Homework Statement A small homemade firework goes off 3 meters about the surface of the water where a person is diving. The diver is 10 meters below the surface of the water. (a). How much time passes from the instant the firework goes off until the diver sees it? (b). How much time...

Let's say i am in a car traveling at 0.5c relative to a truck- which is at rest relative to the ground- approaching me from the opposite direction. Relative to me, the truck is going at 0.5c. Both, truck and car, frames of references are inertial frames of reference. Therefore, the principle of...

You are driving along a highway at 27.50 m/s when you hear the siren of an emergency vehicle traveling in the opposite direction on the other side of the highway. When the vehicle is approaching you, you hear the frequency of the siren as 2800 Hz, but when it is past you the frequency becomes...