Doppler Definition and 713 Threads

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...

I chose to write an essay on the "interesting" question I stumbled upon For part of it I am trying to calculate the Doppler shift in light with the relative motion of C. I suppose in the effort to not drone on for days I will first limit it to small, more simple questions and later,if we...

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...

Homework Statement How fast would a motorist have to be traveling for a yellow (l = 595 nm) traffic light to appear green (l = 550 nm) because of the Doppler shift? Homework Equations v=[(c)(f0/fs)2-c] / [(f0/fs)2+1] The Attempt at a Solution v= Speed of motorist c= Speed of light...

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...

"Basic" problem regarding doppler effect of light (E/M waves) 1. At what speed would one have to move at to see a red light as green. Presume red light wavelength = 630nm and green light wavelength = 530nm. 2. f0=fs√([1+v/c]/[1-v/c]) >f0 = observed frequency >fs = source frequency >v...

what does the doppler effect mean for an individual photon? for instance in a blue shift do the photons actually have more energy if they were originally a lower frequency?

I remember reading in a book that if we approached a red light really fast it would appear green to us due to the Doppler effect of light does anyone know how fast we would need to travel for this to happen.

Presenting the aberration of light effect we consider that two observers at rest in I and I' in the standard configuration equipped with laser guns start to emit light when they are instantly located at the same point in space. The problem is to find out a relationsship between the directions...

Homework Statement A car is driving down the road at 25m/s. Inside the car, the radio is blaring music at 1800Hz. How would it sound to a person standing still a) in front of the car b) behind the car?Homework Equations [fo/(vw+vo)] = [fs/(vw-vs)]The Attempt at a Solution a) [fo/(vw+vo)] =...

Homework Statement A radar beam has a wavelength of .02 m. The frequency is 17500 Hz. What would be its echo frequency if a rocket 60km away is moving at 500m/s and the radar is coming from a jet moving at 310m/s towards the rocket which is aimed at it? (b) Would the rocket appear red shifted...

Homework Statement A train approaches, and passes through, a station. During this period the velocity of the train is constant and the engine is continuously sounding its whistle. Which one of the following correctly describes what an oberver on the platform will hear? Sound heard as...

Homework Statement An ambulance with a siren emitting a whine at 1530 Hz overtakes and passes a cyclist pedaling a bike at 2.22 m/s. After being passed, the cyclist hears a frequency of 1519 Hz. How fast is the ambulance moving? (Take the speed of sound in air to be 343 m/s.) Homework...

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 470 Hz; as the truck recedes, you hear a tone of 400 Hz. How much time will it take the truck to get to the fire 2.5 km away assuming...

Homework Statement A car moving at 35 m/s approaches a stationary whistle that emits a 220 Hz sound. The speed of sound is 343 m/s. What is the speed of sound relative to the driver of the car? Homework Equations fo = fs [1 +/- vo/v] / [1 +/- vs/v] The Attempt at a Solution Dont...

Homework Statement Horseshoe bats use the Doppler Effect to determine their location. A horseshoe bat flies toward a wall at a speed of 15 m/s while emitting a sound of frequency 35 kHz. What is the beat frequency between the emission frequency and the echo? Assume that the air temperature is...

The security alarm on a parked car goes off and produces a frequency of 952 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 97 Hz. At what speed are you driving? F=Fo [(Vsound-...

Hello, This paper presents an experimental setup and claims that Special Relativity would predict a second order Doppler shift: http://www.atomicprecision.com/blog/wp-filez/Thim%20-%20Absence%20of%20the%20relativistic%20Doppler%20effect%20...%20.pdf Since the emitter and receiver have...

The formula which accounts for the Doppler shift is derived from the invarainace of the phase of a plane wave. [1] The plane wave is a mathematical construction associated with an infinite source os oscillation or with a very high source-receiver distance. The same formula is derived...

hi friends which is nice book for explanation of doppler effect please help me

I am new to the field of relativity. I read the Lorentz transformation between different system of coordinates. I have a question. Let's suppose that we have a Doppler shifted pulse in frequency (time dilation). This pulse has the same amplitude as the pulse seen by a moving observer. That is...

At a distance of 20m from a source of sound, the sound level is 40dB. If the observer backs up to a distance of 40m from the source, what will the sound level be? Basically, I said that the sound level halved = 20dB. Correct?

You are standing on railroad tracks as a train approaches at a constant velocity. Suddenly the engineer sees you, applies the brakes, and sounds the whistle. What do you hear starting at that moment? Because the waves are "stretching" as it approaches you slower and slower, I said that the...

Homework Statement Ok here's the problem.. a little lengthy so bear with me :) (3 parts need help w/ last two) Expectant parents are thrilled to hear their unborn baby's heartbeat, revealed by an ultrasonic motion detector. Suppose the fetus's ventricular wall moves in simple harmonic...

Homework Statement A Doppler blood flow unit emits ultrasound at 5.0 {\rm MHz}. What is the frequency shift of the ultrasound reflected from blood moving in an artery at a speed of 0.20 m/s? What equations would I use to calculate the doppler shift? It is not in my textbook...

I know which equations to use for solving Doppler Effect problems, so figuring out which is the observer and which is the source and which is moving or stationary is not the problem, the problem I am having is in solving the actual formulas... This question might belong in the math help section...

1. http://www.prep101.com/MCAT/102MCATPhysicsAnswers.pdf number 15 2. As you can see I already have the answers, I think I'm just doing something wrong. 3. I already know that the answer will be 'away' making it either a or c. So first I plugged the equation given (f1 =...

Homework Statement The security alarm on a parked car goes off and produces a frequency of 735 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 78.4 Hz. At what speed are you driving? 2. The attempt at...

Hi I'm looking at the structure of the Zeeman effect on the two yellow lines in the sodium spectrum. I'm using a Fabry-Perot etalong and a sodium lamp. The thing is, when I have just started the lamp, and don't have a magnetic field applied, i only see the two rings expected from the fine...

Light sources A & B begin at the same location. Then, source A begins moving directly (and soon inertially) away from Observer at 0.8c, while source B begins moving directly (and soon inertially) toward Observer at 0.8c. SR Doppler redshift causes the light received by Observer from A to be...

Were there any experiments that proved doppler shift of light on a fast moving object - that it has higher frequency if the object is moving towards you and lower if the object is moving away?

Homework Statement Suppose a heart's ventricular wall moves in simple harmonic motion with amplitude 1.8mm and a frequency of 115 per minute. (a) Given a motion detector in contact with the chest produces sound at 2,000,000Hz which travels through tissue at 1.50 km/s. Find the maximum linear...

John is listening to a horn. He knows the frequency of the horn is 300 Hz when both he and the horn are at rest. If he hears a pitch of 330 Hz, there are clearly several possibilities. (Give ALL correct answers, i.e., B, AC, BCD...) A) Both can be moving and have the same speed. B) Both can...

I do not fully understand the Doppler effect in light. A theoretical question: If I was traveling near the speed of light, towards a source of light. Would all the wavelengths in the visible spectrum be shortened and therefor, everything shifting towards red? I thought the speed of...

Homework Statement Do not attempt to do this experiment! You are sitting on railroad tracks, and extremely fast trains are approaching from both the left and the right. These trains have equal speeds, and both send out a warning signal with their horns. You hear this signal at a frequency...

Homework Statement Two adjacent sources each emit frequency 800 hz in air (340 m/s). how far would source 1 have to be moved so an observer in front of the sources would hear no sound? .321 .213 .123 or .312. Homework Equations f' = f/(1+ vsource/vsnd) The Attempt at a Solution i...

Homework Statement Hydrogen's only visible spectral lines are 656, 486, 434, and 410 nm. If spectral lines were of absolutely precise wavelength, they would be very difficult to discern. Fortunately, two factors broaden them: the uncertainty principle and the doppler broadening. Atoms in...

Homework Statement Assuming the speed of sound is 338 m/s: A bat moving at 6.2 m/s is chasing a flying insect. The bat emits a 53 KHz chirp and receives an echo at 53.6 KHz. At what speed is the bat catching up on its prey? Homework Equations f^{'}=[ (V_{Air} + V_{observer}) /...

Homework Statement An object is moving at speed vo toward a source at rest that is emitting sounds waves with frequency fo. What is the doppler shifted frequency of the reflected wave that comes back to the source? Homework Equations The Attempt at a Solution If I use the...

Homework Statement Speed of sound in air is 340m/s. Sound from a jet, moving a 100m/s through the air, will have a speed of: Homework Equations Doppler effect, and v = Sqrt(bulk/density) The Attempt at a Solution The answer for this is 340m/s. I was wondering why. Because all the...

Homework Statement A source of sound mvoes along one straight line between listeners Abigail and Bertha. The wavelength of the sound waves heard by Abigail is about 1/2 the wavelength heard by Bertha. What is the ratio of of the speed of the source to the speed of sound? Assume that the air...

Homework Statement The calibration for a piece of ultrasound equipment states that the velocity of blood flow in the aorta is normally about 0.28 m/s, and that the detector emits a frequency of 4.20 MHz. a) If the ultrasound waves were directed along the blood flow and reflected from the...

If not Doppler, what type of transformation does Hubble's law utilize?

Wouldn't the Doppler effect stop us from seeing the beginning of the universe unless it starts approaching us? (or unless the universe stops expanding and begins retracting?)

Random question that I thought of while trying to fall asleep last night. :) We all know that galaxies moving very fast away from us exhibit visual redshift. If gravity waves / gravitons are real, they must then have a frequency of some kind. Does the frequency of a gravity wave affect...

Homework Statement A radar at rest emits microwaves at a frequency of 1.63 GHz onto a truck moving away from the radar. There is a frequency difference between the received and sent frequencies of 281 Hz. What is the velocity of the truck? Homework Equations f(obs)=f(sent)*[(v+/-observer...

Homework Statement A source of 1-kilohertz sound is moving straight toward you at a speed .9 times the speed of sound. The frequency you receive is: Homework Equations \nu = \frac{v}{\lambda} f' = \frac{v + v'}{v} f The Attempt at a Solution When I attempt the...

Hello, I am well and truly stumped on Doppler shift. The complete expression is f'=f \gamma (1-\beta cos(\theta)) where: \beta=v/c v=source\ velocity \gamma=\frac{1}{\sqrt{1-\beta^{2}}} \theta is the angle between received photons (lab frame) and the direction of motion of...