Doppler Definition and 713 Threads

I know that Bragg cell used in laser doppler vibrometer (LDV) is used to give information about the direction of the velocity of the object that we measure. I also know that Bragg cell will shift the frequency of the laser beam(modulation frequency is reduced) when the object is moving towards...

[SOLVED] Doppler Effect? Homework Statement A bat flying at 4.0 m/s emits a chirp at 20 kHz. If this sound pulse is reflected by a wall, what is the frequency of the echo received by the bat? Homework Equations Not sure. Do I use the f(1)=f*[(v+/-observer velocity)/(v+/-source...

Homework Statement A distant star at rest with respect to an observer on Earth emits light of frequency 6.690 x 10^14 Hz. The star breaks up into two remnants of equal mass, which are observed to emit light of frequency 7.135 x 10^14 Hz and 4.282 x 10^14 Hz Find the velocities of the...

Homework Statement The full expression for the relativitic Doppler Shift is v' = v \gamma [1- \beta cos \theta] where v' and v are the frequencies of the light source in its own rest frame and and in the laboraty respectivley. \theta is the (laboratory) anglebetween the direction of...

Hello all, I first must state I have very little formal experience or knowledge of physics or mathematics. This is just a random musing that I could not find an answer for. My question is that if a source emitting waves is moving, and the waves when observed are affected by the...

I'm trying to detect a remote moving target. I know that if I send out a light beam against a distant target that is moving towards or away from me that the reflected light will be frequency shifted by a small amount. Now what if I amplitude modulated the light with an audio frequency. Would...

[SOLVED] Relativistic Doppler Effect and a Baseball Homework Statement A baseball coach uses a radar device to measure the speed of an approaching pitched baseball. This device sends out electromagnetic waves with frequency f_0 and then measures the shift in frequency \Delta f of the...

[SOLVED] Doppler Shift and Beats Homework Statement A car horn sounds a pure tone as the car approaches a wall. A stationary listener behind the car hears an average frequency of 250Hz, which pulsates (beats) at 12 Hz. What is the speed of the car? The speed of sound is assumed to be 331...

Assume 2 massive bodies are moving away from each other at high speed. Since the gravitons which cannot travel at faster than the speed of light, are having a hard time being exchanged by these two bodies, it must be plausible to assume that the gravitational pull between these two bodies...

6) Using Hubble’s law, estimate the wavelength of the 590 nm sodium line emitted from galaxies (a) 2*10^6 lightyears away from Earth, (b) 2*10^8 lightyears away, and (c) 2*10^9 lightyears away. ** Use the relativistic Doppler formula for light emitted from a receding source)

When a police car passes you with a siren with a frequency of 440 Hz, a noticeable drop in the pitch of the sound of the siren will be observed as the car passes by. But why the pitch suddenly drops when the car is passes by? I am not pretty sure why I heard the pitch suddenly drops, but I...

Homework Statement A speeder is pulling directly AWAY and INCREASING his distance from a police car that is moving at 27 m/s with respect to the ground. The radar gun in the police car emits an electromagnetic wave with a frequency of 7.2 x 109 Hz. The wave reflects from the speeder's car and...

[SOLVED] Doppler Effect Problem Homework Statement A submarine (sub 1) travels through water at a speed of 8.00 m/s, emitting a sonar wave at a frequency of 1400 Hz. The speed of sound in the water is 1533 m/s. A second submarine (sub 2) is located such that both submarines are traveling...

I have to get a doppler test done on my left leg. Has anyone had one done? Sounds like it's just a type of ultrasound. And I need a CAT scan. The CAT scan scares me since from watching House on TV, that is where most patients end up with blood flowing out of their eyes and ears. I think...

A whistle of frequency 577 Hz moves in a circle of radius 73.2 cm at an angular speed of 16.1 rad/s. What are (a) the lowest and (b) the highest frequencies heard by a listener a long distance away, at rest with respect to the center of the circle? (Take the speed of sound in air to be 343 m/s.)...

I've been trying this for 3 hours and I'm getting nowhere. These are the graphs I made for Hydrogen Intensity vs Frequency for a radio telescope that transits the sun and galactic arms of the galaxy. http://img220.imageshack.us/img220/5904/helpgraphia6.jpg...

Homework Statement Assume: Take the speed of sound in air to be 341 m/s. A bat, moving at 6.3 m/s, is chasing a flying insect. The bat emits a 47 kHz chirp and receives back an echo at 47.73kHz. At what speed is the bat gaining on its prey? Answer in units of m/s. Homework Equations...

Homework Statement A train is moving parallel and adjacent to a highway with a constant speed of 25 m/s. A car, at time t0, is 42 m behind the train, traveling in the same direction as the train at 49 m/s, and accelerating at 4 m/s^2. The train's whistle blows at a frequency of 460Hz. The...

The Doppler shift formula relates two proper time intervals measured in I and I' respectovely (tau)=D(tau)' D representing a Doppler factor that depends on the relative speed of I and I'. By definition the events involved in I and I' respectively take place at the same point in space. If the...

[SOLVED] Horsehoe Bats, Insects, Speed... and the Doppler Effect Homework Statement Horseshoe bats (genus Rhinolophus) emit sounds from their nostrils, then listen to the frequency of the sound reflected from their prey to determine the prey's speed. (The "horseshoe" that gives the bat its...

Homework Statement The Doppler shift was first tested in 1845 by the French scientist B. Ballot. He had a trumpet player sound an A 440 Hz while riding on a flatcar pulled by a locomotive. At the same time, a stationary trumpeter played the same note. Ballot heard 3.0 beats per second. How...

Can anyone tell me what the doppler wavelength shift equation is? thanks

I am just beginning to learn about quantum mechanics and I have already come up with a question regarding it. I know that light is absorbed by an electron at once and I know about the doppler shift. Yet is light emitted at once, or gradually? If at once, how could the wavelength be shifted...

how much is a nebular line widened by the doppler broadening due to thermal motion of gas particles? What is the spectrographic resolution required to resolve the line? I do not understand how to solve this problem. I've been given specific numbers of an HII region. How do I find the...

Homework Statement I have a problem that asks to derive the doppler effect for the two different cases of a moving observer and a moving source. Homework Equations I should get f' = f*(v +/- vo)/(v +/- vs) as my general equation, where f' is the observed frequency and f is the...

[FONT="Times New Roman"]I have a few questions concerning the Doppler Effect, I know what it is in terms of a moving object, and how speed effects fequency etc. but I'm more interested in the explantions. My actual knowledge of the two explanations is reasonably vague. The one I am interested...

I am having a friendly argument with a friend. If a light source was moving towards a colored object at high speeds in a completely dark area, would the color shift due to the Doppler effect be doubled? Possible theories are no (which we agree is wrong) Yes (which may be right) Or simply...

A distant galaxy is moving away from us at a speed of 1.85x10^7m/s. Starting from the formula for the doppler shifted frequency, derive a formula for the change in wavelength and hence calculate the fractional redshift (λ'-λ₀)/λ₀ in the light from the galaxy. I'm pretty confused at the moment...

Homework Statement Ultrasound waves are used to measure blood-flow speeds. Suppose a device emits sound at 450 kHz, and the speed of sound in human tissue is taken to be 1540 m/s. What is the expected beat frequency if blood is flowing normally in large leg arteries at 3.0 cm/s directly away...

Homework Statement A source and an observer are each traveling at 0.52 times the speed of sound. The source emits sound waves at 1.2 kHz. (a) Find the observed frequency (in kHz) if the source and observer are moving toward each other. (b) Find the observed frequency (in Hz) if the...

Homework Statement A man is traveling on a bicycle at 14 m/s along a straight road that runs parallel to some railroad tracks. He hears the whistle of a train that is behind him. The frequency emitted by the train is 840 Hz, but the frequency the man hears is 778 Hz. Take the velocity of...

Doppler Effect...Ahhhh! Homework Statement A student in a parked car honks the horn, which has a `proper' frequency of 310.00 Hz. An observer in an approaching vehicle measures the frequency of the sound to be 342 Hz. Calculate the speed of the approaching vehicle. Use 340 m/s as the speed of...

Homework Statement The pitch of the sound from a racecar engine drops the musical interval of a fourth when it passes the spectators. This means the frequency of the sound after passing is 0.75 times what it was before. How fast is the racecar moving? 1. 61 m/s 2. 49 m/s 3. 72...

suppose i am moving in a train and at the same time playing a violin .Is the dopller effect/formulae applicable for me

A high speed train is traveling at a speed of 41 m/s when the engineer sounds the 416 Hz warning horn. The speed of sound is 345 m/s. What is the frequency of the sound as perceived by a person standing on at the crossing when the train is leaving? I used the equation: f0=fs/(1-vs/v) f0=416...

Homework Statement A 1.50-MHz sound wave travels through a pregnant woman’s abdomen and is reflected from the fetal heart wall of her unborn baby. The heart wall is moving toward the sound receiver as the heart beats. The reflected sound is then mixed with the transmitted sound, and 85 beats...

[SOLVED] Doppler Effect in Circular Motion Homework Statement A Physics professor annoys his students by tying a 500 Hz generator to a 60cm long string and whirling it around his head at 100 rpm. What are the highest and lowest frequencies heard by the students? Homework Equations...

BACKGROND: Myself and a number of others are doing a thing called Dynamic Soaring with our special purpose built radio controlled gliders. We are getting them going very fast; in the range of 300-320mph. We have verified a top speed of 309mph using radar guns but that is the highest that...

Homework Statement I am told that to a stationary observer, the lights infront of a spaceship has the wavelength = 480 nm when it arrives, and the lights in the back have wavelength 640 nm when the ship is moving away. Both lights (front and back) are the same. I have to find the wavelength...

A speeder is pulling directly away and increasing his distance from a police car that is moving at 23 m/s with respect to the ground. The radar gun in the police car emits an electromagnetic wave with a frequency of 6.0 109 Hz. The wave reflects from the speeder's car and returns to the police...

Hi, and thank you for your time to read this. I'm having a difficult time figuring out the answer to this question; Q: A porpoise swims toward a school of fish and emits a high pitched sound. The porpoise listens for the echo of its own squeak. I have to predict whether the observer will...

the formula of Doppler Effect f = fs(v + vd)/(v - vs) (v = speed of sound; d = detector; s = source) Simply from this formula, it can be seen that vd has differenct effect on the frequency receiver from vs. when vd or vs approaches the speed of sound, this difference is pronounced. make...

Defining the period measured by a moving observer relative to a stationary source as T=t(n)-t(n-1) where t(n) and t(n-1) represent the times when two successive wavecrests are received respectively, the theory of the Doppler Effect leads zero and negative periods in the case of sonic and...

a Concept Question. Is there a Doppler Shift if the source and observer move in the same direction with the same velocity? Explain . Can someone drop their comments and ideas ..? please and thanks you.

Homework Statement An astronomer observes a hydrogen line in the spectrum of a star. The wavelength of hydrogen in the laboratory is 6.563 x 10-7m, but the wavelength in the star’s light is measured at 6.56186 x 10-7m. Which of the following explains this discrepancy? A) The star is...

DISCLAIMER: i may very well have exactly zero idea what I'm talking about. please feel free to berate me if i am way off base... so i know the doppler effect is normally used to determine an unknown radial velocity, but I'm assuming that if i know the velocity of the source, i can use the...

Homework Statement You're flying in an aircraft at 46 m/s. An eagle flies directly towards you at 11 m/s. Speeds are relative to ground. The eagle emits a cry at 3400 Hz, and the speed of sound is 330 m/s. What frequency do you hear? Homework Equations f_o = f_s\left(...

Homework Statement A parked car's alarm goes off, producing a sound at 961 Hz. As you drive toward, pass, and drive away from this parked car, you observe a frequency change of 98 Hz. At what speed are you driving? (Speed of sound is 343 m/s.) Homework Equations f_o = f_s\left(...

Homework Statement Hello, I'm researching about relativity and Doppler effect, most text and book gives the equation for it as (term with square root is on the numerator, and the term w/o is on the denominator) while on some text, has the reverse of the fraction part (which is the...

Homework Statement A radio played on a moving train has frequency of 85 Hz. A second radio played at train station is at rest. What is the beat frequency heard if train approaches the station at 10 m/s? Homework Equations f' = [f \ (1-vsource/vsound) I used this equation because the...