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...
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.)...
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...
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...
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...
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 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...
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...
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...
Homework Statement
A distant galaxy moving away from us at speed 1.85 *10^7 m/s. Calculate the fractional redshift (lambda'-lambda(0))/(lambda(0)) of the light from this galaxy.
Homework Equations
(lambda'-lambda(0))/(lambda(0))=lambda'/lambda(0)-1;
f=(sqrt(1-beta)/sqrt(1+beta))*f(0)...
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...
doppler effect / expanding universe . trouble uniting both concepts?
Ok, I think I understand both; I just don't understand their relationship.
As I understand the doppler effect, in short, its cause by the difference in velocity (movement through space).
And as I understand the expansion...
I am playing with a small personal fan and I noticed that when the blades are moving at some frequency that "lines up" with my monitor refresh rate frequency, they appear blurry and stationary, but with altered shapes. Not only that, but certain edges of the blades are colored blue, while the...
So the Red shift of extragalactic bodies means that they are moving away from us. And this effect is seen for all extra galactic objects minus the local group of galaxies. How then is it known that our local group is not the center of the universe? Wouldn't the fact that everything is moving...
Hi, I am a little confused about some aspects of sound waves. I was hoping to just check to see if I am on the right track.
I have a problem where a guy is moving towards the great wall of china, with a air horn, emitting a constant frequency sound of 500Hz. The sounds is going to hit the...
Doppler effect homework problem help (still lost)
Homework Statement
A block with a speaker bolted to it is connected to a spring having spring constant k = 17.0 N/m, as in Figure P17.40. The total mass of the block and speaker is 44.00 kg, and the amplitude of this unit's motion is 0.475...
Homework Statement
At the Indianapolis 500, you can measure the speed of cars just by listening to the difference in pitch of the engine noise between approaching and receding cars. Suppose the sound of a certain car drops by a factor of 1.50 as it goes by on the straightaway. How fast is it...
Homework Statement
Is this true?
the observed doppler shift for sound waves depends only on the relative motion of the source and the receiver.
Homework Equations
this is a concept-like question
The Attempt at a Solution
If no, doesn't mean, wind will affect the doppler effect?
Using a highly sensitive parabolic sound collector, Tom records the frequency of a tuning fork as it drops into the Grand Canyon. He drops the vibrating tuning fork from rest at t=0. He records a frequency of 1887.0 Hz at t=7.880 s. What is the natural frequency of the tuning fork? Use...
Assume: Take the speed of sound in air to be 343 m/s.
A bat, moving at 5.9 m/s, is chasing a flying insect.
The bat emits a 46 kHz chirp and receives back an echo at 46.26 kHz.
At what speed is the bat gaining on its prey? Answer in units of m/s.
I tried this:
f=initial frequency...
Hey guys...or ladies...um...just wondering what I hav done wrong for the following Q, it is an online Q i am doing and it tells me my answer is incorrect?
Q) "A car alarm is emitting sound waves of frequency 520 Hz. You are on a motorcycle, traveling directly away from the car."
"How...
Homework Statement Suppose that a police car on the highway is moving to the right at 28 m/s, while a speeder is coming up from almost directly behind at a speed of 34 m/s, both speeds being with respect to the ground. The police officer aims a radar gun at the speeder. Assume that the...
I have a question regarding the doppler effect and frequency:
You (a stationary observer) are standing by the railroad tracks and hear a frequency of 1000 Hz as the train approaches... as the train goes away, the frequency changes to 800 Hz. Knowing that the speed of sound is 340 m/s, how...
A train is traveling at 30.0 m/s relative to the ground in still air. The frequency of the note emitted by the train whistle is 262 Hz.
a. What frequency (fapproach) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first...
I would need a pointer to a mainstream treatment of the general relativistic Doppler effect when source and receiver are accelerated wrt each other. Book/paper/wiki . No crank papers , please (i.e. no Apeiron and such). Thank you.
I'm working through the derivation found on this site:
http://maths.dur.ac.uk/~dma0cvj/mathphys/supplements/supplement5/supplement5.html
And though most of it is clear to me, I stumbled upon a little problem.
My question is about the section that starts with "This is all according to...
I have heard that if one is hypothetically placed in a box completely solid, whith a shield that leaves everything that would have entered a normal box, like light, or neutrinos, out of it. If you sent that in a certain speed, with nothing affecting it, just traversing through space, the person...
I cannot search the forum to check if this has been posted before, because I do not know what it is called in english...
That means that i have to try to explain what i means, here it goes: When a light producer, like a star is moving, it sends out waves that is either compressed or expanded...
Hello I have a question that is giving me trouble:
Light of wavelength 659.7 nm is emitted by a star. The wavelength of this light as measured on Earth is 661.1 nm.
How fast is the star moving with respect to Earth? km/s
Is it moving toward Earth or away from it?
Here's where...