Doppler Definition and 749 Threads

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...

1. Homework Statement At the Winter Olympics, an athlete rides her luge down the track while a bell just above the wall of the chute rings continuously. When her sled passes the bell, she hears the frequency of the bell fall by the musical interval called a minor third. That is, the...

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...

1. Whenever we talk about a single frequency characterizing an electromagnetic wave, we are tacitly assuming that the source and the detector are stationary relative to one another. However, if the distance between the two is changing in velocity, V, then the frequency of radiation, ν1 emitted...

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...

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)

Homework Statement Two trumpet players tune their instruments to exactly 440 Hz. Find the difference in the apparent frequencies due to the Doppler effect if one plays her instrument while marching away from an observer and the other plays while marching toward the observer. Is this enough to...

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...