Doppler effect Definition and 486 Threads

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...

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...

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...

Homework Statement A speaker is attached to a wire 1.5 m long and is spun in a circle at 2 rev/s. The speaker is connected to an electric piano on which a child is playing a note at 261 Hz. Speed of sound in air is 343 m/s. What range of frequencies will the stationary observer hear? I...

[SIZE="4"]Could anyone who knows give me a really simple yet realistic explanation of the doppler effect. This is one of those things that just boggles the brain so to speak.

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...

I'm having a hard time understanding some things regarding the doppler effect. Please excuse my Microsoft paint diagram, I'm no artist. http://img686.imageshack.us/img686/3949/diagram.jpg http://img686.imageshack.us/img686/3949/diagram.jpg" Given this scenario, which...

Homework Statement An observer is in rest.A source of sound is in rest.A wind blows along the line joining the observer and the source.What all remain same in these: a.frequency b.velocity of sound c.wavelength Homework Equations f prime=f(v+w-vo)/(v+w-vs) Doppler effect The...

Homework Statement A car speeds towards the outside wall with its horn sounding a frequency of 160 HZ. The sound waves reflected off the wall cause the driver to hear 8.0 beats per second. There is no wind and the speed of sound is 343 m/s. Find the speed of the car. Homework Equations...

i am now studying the Doppler effect in a thermal atomic gas If an atom travels in velocity v along x direction at some time, it emits a photon in some direction the momentum of the emitted photon can be well approximated with the free one thus the momentum of the atom after the...

i am now studying the Doppler effect in a thermal atomic gas If an atom travels in velocity v along x direction at some time, it emits a photon in some direction the momentum of the emitted photon can be well approximated with the free one thus the momentum of the atom after the...

Homework Statement Hearing the siren of an approaching fire truck, you pull over to the side of the road and stop. As the truck approaches, you hear a tone of 460 Hz; as the truck recedes, you hear a tone of 420 Hz. How much time will it take for the truck to get from your position to the fire...

Can someone give me an idea on our Investigatory project about Doppler Effect...? Our project shouldn't be amounting in an expensive one. I am only 4th year high school student and so confuse what project will i make... Please Help me guys. Thanks in Advance Guys!

sorry lots of reading but i wanted to explain what I've done (tried to do) Homework Statement An ambulance has a loud siren, which emits a pure note at 5100Hz. A man 20 m from a straight road along which the ambulance is travelling, and records the frequency of the sound he hears from the...

Homework Statement Sally is a police officer who is standing in an intersection. A car driven by David approaches the intersection at a speed of 75 km/h. Sally blows her whistle (at a frequency of 900 hz) and signals the driver to stop. What does frequency does David hear? (speed of sound is...

Homework Statement A car is approaching a reflecting wall. A stationary observer behind the car hears a sound of frequency 745 Hz from the car horn and a sound of frequency 863 Hz from the wall. 1. How fast is the car traveling? A. 25.2 m/s B. 33.4 m/s C. 18.9 m/s D. 54.2 m/s 2...

1. The problem statement 1) A train whistle has a frequency of 1000 Hz. If the train is speeding at a velocity of 60 km/h past a stationary railroad crossing attendant, what is the apparent frequency a) as the train approaches him, b) as it moves away from him? Assume speed of sound to be...

lol :-p http://improbable.com/2009/11/13/doppler-effect-with-a-dogs-squeak-toy/

A very basic question (I hope this is the right place for it). A distant star emits, say, a high-energy x-ray. Due to expansion of space, this reaches us as visible light (say, red part of the spectrum). The light that reaches us has less energy per photon (E=h*nu) then the light emitted...

Homework Statement The Enterorise NCC1701 is cruising 0.6c above the moon of Eridani when it spots a Klingon warbird sunwards. i. It fires a proton torpedo at speed 0.75c relative to the ship at the Klingon warbird. Assuming the proton torpedo does not accelerate, at what velocity must the...

Homework Statement An astronaut is said to have tried to get out of a traffic violation for running a red light (lambda= 670nm) by telling the judge that the light appeared green (lambda= 540nm) to her as she passed by in her high powered transport. If this is true, how fast was the astronaut...

Homework Statement Three radio-equipped plumbing vans are broadcasting on the same frequency f_0. Van 1 is moving north of van2 with a speed of v, van 2 is fixed, and van 3 is moving west of van 2 with a speed of v. What change in frequency (f-f_0) does van 3 hear from van 1? Homework...

Homework Statement You are in charge of calibrating the radar guns for a local police department. One such device emits microwaves at a frequency of 2.15 GHz. During the trials, these waves are reflected from a car moving directly away from the stationary emitter. You detect a frequency...

we know...when a source is running towards the listener...the wavelenth of sound become small and number of waves inceases...as far as i know ..the logic behind is..when a source runs..then waves become congested in a small distance between source and listener...it is so far so ridiculous to me...

One paper claims that the flyby anomaly only exists because NASA scientists forgot about the transverse Doppler effect. If that's true, why is it still called an anomaly? Why isn't everyone banging their heads on walls and thinking, "D'oh! I can't believe I forgot about that!"? If it's not...

When an ambulance approaches, its siren sounds shriller than when I relatively motionless to it, and vice versa. Such is an example of doppler effect, isn't it? However, there one thing I am not sure: does the siren gradually becomes more shriller when the ambulance approaches, or not...

doppler effect quick question! Homework Statement An ambulance traveling at speed 31 m/s is producing a loud sound of frequency 895 Hz. You see the ambulance in your rear view mirror as the ambulance approaches you and you slow down to 14 m/s as a law obeying citizen (hehehe we know now)...

Homework Statement An ambulance is running on an expressway at a speed of 60 km/h from east to west (from A to B) with a siren of 880 Hz. Let the frequency of the siren sound detected by an observer located at a point O be Va and Vb when the vehicle just passes point A and point B respectively...

If the energy of an EM wave = h x f and when a light emitting body (of a particular power) is moving toward or away from the observer the observed frequency changes, does the energy change? If so where does the gained or lost energy come from?

I have a problem in regard to the doppler effect,which may be generalised to all waves--sound,water etc. Please explain why the observed frequency increases as the object approaches an observer and then decreases as the object passes the observer.Actually,I thought that since doppler effect...

Hi, I've got a problem that I can't seem to find an explanation to, about the Doppler Effect An ambulance is going down the road at a speed U meters/second, in the same direction as the wind, which has a speed of W meters/second. The speed of sound in air is c meters/second Now, I have to...

Homework Statement A loud speaker is connected to a string (spring constant k = N/m). The speaker moves back and forward in simple harmonic motion with an Amplitude of 0.8m. The frequency of an oscillation for amass on a string is w = (k/m)^1/2. The mass of the speaker is 90.0g. What is...

Homework Statement A bat flies toward a wall, emitting a steady sound with a frequency of 25.0 kHz. This bat hears its own sound plus the sound reflected by the wall. How fast should the bat fly, v_b, to hear a beat frequency of 220 Hz? Take the speed of sound to be 344 m/s...

Hi, I'm new to these forums. I just had a question about the Doppler effect on light (red and blue shifts of light). I've read how it is supposed to work, but I also read in a book that the speed of light is constant in all moving frames. So if you've got a galaxy moving towards you, and...

Doppler Effect- Observer On Angle To Source Plz help- I've been working on this for 2 days and I'm down to my last teaspoon of coffee powder. Even having the answer didn't help! I think sleepness is turning me into a zombie :eek: ...prehaps eating brains will help me solve this problem...

Homework Statement Standing in line next to the scariest rollercoaster of all time, you see your friends screaming their heads off as they come speeding out of the end of the ride. The sound of their screams is about 30% higher in pitch than normal due to the Doppler shift caused by their...

Homework Statement source emits sound with a characteristic frequency of 640 Hz. Calculate the observed frequency and the wavelength between source and observer in each of the following situations. a) The observer approaches a stationary source at 57 m/s b) Both the source and observer move...

Homework Statement A whistle of frequency 500 Hz tied to the end of a string of length 1.2 m revolves at 400 rev/min. A listener standing some distance away in the plane of rotation hears frequencies in the range ____? (speed of sound=340 m/s) a) 436 to 586 b) 426 to 574 c) 426 to 584 d)...

Homework Statement A boy is walking away from a wall towards an observer at a speed of 1 m/s and blows a whistle whose frequency is 680 Hz. THe number of beats heard by the observer is ____. (Velocity of sound in air=340 m/s) a) zero b)2 c)8 d)4 Homework Equations The Attempt at...

Homework Statement An object producing a sound with frequency 500 Hz is traveling at 40 m/s toward an observer, and the observer is traveling at 30 m/s away from the source. Another source producing a sound with the same frequency is traveling at 10 m/s toward a stationary observer...

How to prove the doppler effect for light wave? Isn't that the speed of light is constant for both the observer and source? If the wavelength for both the source and observer is the same, then the frequency is the same too, so there is no doppler effect? If the wavelength is different...

Astronomers believe that the universe is expanding because of the measured doppler effect redshift of light emitted from distant stars in other galaxies, correct? Do they have other reasons for believing that the universe is expanding? The stars in our own galaxy are known to not be traveling...