Doppler effect Definition and 486 Threads

Homework Statement A car stops at 50m to a road-railway junction. A train is moving with a constant velocity 35m/s towards the junction. If the train emits a siren at a frequency of 100Hz, calculate the maximum and the minimum frequency that can be heard by the car driver. velocity of...

Homework Statement Revered members, I have attached the image of Doppler effect explanation. Homework Equations I have the following doubts 1)t1 = L/v 2) t2 = T0 +( L + vsT0)/v But why T0 comes here, instead of ( L + vsT0)/v The Attempt at a Solution

Hi, I am doing doppler effect and this question wants me to prove that the wavelength perceived by the observer and that of the wave emitted is the same. I tried doing it but couldn't, so I checked out what they had as an answer: They said that the wavelength of the emitted wave is: v...

Homework Statement Question: Two trains on separate tracks move toward one another. Train #1 has a speed of 130 km/hr and train #2 a speed of 90km/hr. Train 2 blows its horn, emitting a frequency of 500 Hz. What frequency is heard by the engineer on train #1? Homework Equations This is...

I have a question that has been bugging me for a while. You see, I have a predisposition of trying to visualize everything that I learn. I have no problem visualizing space-time, black-holes distorting space-time, the universe expanding, etc..., but when it comes to the Doppler Effect I want to...

While studying the Doppler effect at school, it struck me as strange that the following two problems have different solutions: a) you are moving at 40 m/s toward a source that is making a sound with a frequency of 1000 Hz. What frequency do you hear? (speed of sound= 340 m/s) b) The...

Homework Statement A policeman with a very good ear and a good understanding of the Doppler effect stands on the shoulder of a freeway assisting a crew in a 40-mph work zone. He notices a car approaching that is honking its horn. As the car gets closer, the policeman hears the sound of the...

Does the amplitude of a wave changes when the source is moving? I am mainly interested in waves in a medium (e.g. sound, water...) No text about Doppler effect I have found mentions anything about the amplitude so I guess it does not change. However in the case if the speed of the source...

Frequency changes relative to the observer due to the doppler effect. Does wavelength?

Homework Statement A tuning fork vibrating at 506 Hz falls from rest and accelerates at 9.80 m/s2. How far below the point of release is the tuning fork when waves of frequency of 488 Hz reach the release point? (Take the speed of sound in air to be 343 m/s).Homework Equations...

Homework Statement Bird A and B are flying towards each other Bird B at 20m/s Bird A at 15m/s and screeches with a frequency of 3200 Hz what does bird B perceive? Homework Equations the speed of sound is 343m/s Fobserver==Fsource((vsound+vobserver)/(vsound+vsource) The Attempt...

Doppler effect told us that the frequency and wavelength changed but not the speed of wave if the transmitter or receiver is moving. Could I interpret Doppler Effect as follow: Frequency/wavelength change for different observers, however, the speed of wave is constant for all observers. If...

So a factory whistle emits a sound at 875Hz. The temperature of the air is 25.9oC. What frequency will be heard by an observer in a car traveling at 27m/s away from the source i know this is a two step problem but i have no idea where to start! anyone lead me in the right direction?

vw= Velocity of Wave vm= Velocity of Wave Source fw= Frequency of the Wave fd= Frequency of the Wave relative to Detector as Wave Source is also moving q= Infinity For the wave frequency detected by a detector at rest as the wave source* is moving towards it, there is: fd=( vwfw )/(...

Homework Statement A truck moving at 36 m/s is overtaken by a police car moving at 45 m/s in the same direction. If the frequency of the siren relative to the police car is 500 Hz, what is the frequency heard by an observer in the truck as the police car approaches the truck? (The speed of...

I found a question in a Maltese physics past paper dealing with the doppler effect. I managed to figure out the part dealing with the effect of motion of the wave source, but i was asked this: How does The Doppler Effect show us the difference between galaxies that are near and those that are...

my query is : The electric and magnetic fields don’t squeeze or stretch then how is Doppler Effect of light possible? In the phenomenon of Doppler Effect, light emitted from a moving source is detected to have different frequency. If this is taken on terms of detecting the no. of waves...

Homework Statement A siren has two loud speakers attached to a rotating disk. The disks radius is 3m. The speakers emit a sound frequency of 300 Hz.(Speed of sound in air is 344 m/s) A)How fast does the disk need to spin for an observer standing some distance away to perceive two frequencies...

Was it considered that the force of gravity could vary according to the redshift equation? 1+z=\frac{1+v \cos (\theta)/c}{\sqrt{1-v^2/c^2}} If those who consider this are right, then it would imply that an object leaving a gravitational system would experience a slight decrease in the...

I have a question about of light waves. Moving at high speeds toward or away from visible light could be the difference of experiencing that light as violet or red. Of course this experience is due to the photoreceptors in the eye seemingly experiencing a shorter or longer wavelength. My...

Homework Statement A star is moving away from Earth at a speed of 2.4 x 10^8 m/s. Light of wavelength 480 nm is emitted by the star. What is the wavelength as measured by an Earth observer?Homework Equations fo=fs(1 - vrel/c) I substracted because they the star is moving away from the earth...

The problem: I have to answer a question about the Doppler effect using the formula attached. I know i have to solve for Vw, but I get Vw/Vw=(Fd/Fs)(-Fs) and I am possitive that's not right, can someone please help me out?? Thankyou

A stationary destroyer is equipped with sonar that sends out pulses of sound at 30.000 MHz. Reflected pulses are received from a submarine directly below with a time delay of 60 ms at a frequency of 29.958 MHz. (a) If the speed of sound in seawater is 1.55 km/s, find the depth of the...

Homework Statement A sound source moves at a constant velocity. A listener is standing at a distance L away from it. Given that the source moves in a straight line at a right angle to the listener and starts closest to the listener (ie at t=0) deduce an expression for the frequency heard by 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...

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 +...

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 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...

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

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...

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...

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...

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...

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...