1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Rina8888 [55]
3 years ago
9

The siren on an ambulance is emitting a sound whose frequency is 2250 Hz. The speed of sound is 343 m/s. (a) If the ambulance is

stationary and you (the "observer") are sitting in a parked car, what are the wavelength and the frequency of the sound you hear? (b) Suppose that the ambulance is moving toward you at a speed of 26.6 m/s. Determine the wavelength and the frequency of the sound you hear. (c) If the ambulance is moving toward you at a speed of 26.6 m/s and you are moving toward it at a speed of 11.0 m/s, find the wavelength and frequency of the sound you hear.
Physics
1 answer:
Marina86 [1]3 years ago
4 0

(a) 2250 Hz, 0.152 m

In this situation, both the ambulance and observer are stationary.

This means that there is no shift in frequency/wavelength due to the Doppler effect. So, the frequency heard by the observer is exactly identical to the frequency emitted by the ambulance:

f = 2250 Hz

While the wavelength is given by the formula:

\lambda=\frac{v}{f}

where

v = 343 m/s is the speed of sound

f = 2250 Hz is the frequency of the sound

Substituting, we find

\lambda=\frac{343 m/s}{2250 Hz}=0.152 m

(b) 2439.2 Hz, 0.141 m

The Doppler effect formula for a moving source is

f'=(\frac{v}{v+v_s})f

where

f' is the apparent frequency

f is the original frequency

v is the speed of sound

v_s is the velocity of the source (the ambulance), which is positive if the source is moving away from the observer, negative otherwise

Here the ambulance is moving toward the observer, so

v_s = -26.6 m/s

Substituting into the formula, we find the frequency heard by the observer:

f'=(\frac{343 m/s}{343 m/s-26.6 m/s})(2250 Hz)=2439.2 Hz

while the wavelength seen by the observer will be:

\lambda' = \frac{v}{f'}=\frac{343 m/s}{2439.2 Hz}=0.141 m

(c) 2517.4 Hz, 0.136 m

In this situation, we must use the most general formula for the Doppler effect, which is

f'=(\frac{v+v_r}{v+v_s})f

where

v_r is the velocity of the observer, which is positive if the observer is moving toward the source, negative otherwise

v_s is the velocity of the source (the ambulance), which is positive if the source is moving away from the observer, negative otherwise

In this situation,

v_s = -26.6 m/s

v_r = +11.0 m/s

Therefore, the frequency heard by the observer is

f'=(\frac{343 m/s+11.0 m/s}{343 m/s-26.6 m/s})(2250 Hz)=2517.4 Hz

while the wavelength seen by the observer will be:

\lambda' = \frac{v}{f'}=\frac{343 m/s}{2517.4 Hz}=0.136 m

You might be interested in
You drop your cell phone. Prior to hitting the ground, the phone's kinetic energy will ________ and its potential energy will __
SVETLANKA909090 [29]

Answer:

The kinetic energy of the phone would increase. The gravitational potential energy of the phone would decrease.

Explanation:

The kinetic energy {\rm KE} of an object is proportional to the square of the speed of that object. If air resistance is negligible, the phone would accelerate under gravitational pull and speed up. Hence, the kinetic energy of the phone would increase.

The gravitational field near the surface of the earth is approximately constant. Hence, the gravitational potential energy {\rm GPE} of the phone would be proportional to its height. As the phone approaches the ground, the height of the phone becomes lower and the gravitational potential energy of the phone would decrease.

5 0
1 year ago
What does a black asphalt road become hotter than a white cement sidewalk in the same amount of sunlight?
victus00 [196]
The black means that it is a great emitter/absorber of the electromagnetic spectrum. The electromagnetic radiation is reflected of the white and absorbed nurture black meaning that the temperature of the black tarmac increases to that greater the the white
7 0
3 years ago
Describe asexual reproduction
Brrunno [24]
“Asexual reproduction is a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes, and almost never changes the number of chromosomes.” -Wikipedia
4 0
3 years ago
Object A is positively charged. Object A and Object B
ozzi

Answer: object B is negatively charged, object C is positively charged and object D is also positively charged

Explanation: since unlike charges attract and like charges repel, for object A which is positively charged and B to attract B must be negatively charged and then for B which is negatively charged and C to attract C must be positively charged and for C and D to repel they have to be of thesame charge which means D is positive as well.

4 0
3 years ago
Bird bones have air pockets in them to reduce their weight—this also gives them an average density significantly less thanthat o
snow_tiger [21]

Answer:

41.4 g

41.4 cm³

1.08695 g/cm³

Explanation:

\rho = Density of water = 1 g/cm³

Mass of water displaced will be the difference of the

m=45-3.6\\\Rightarrow m=41.4\ g

Mass of water displaced is 41.4 g

Density is given by

\rho=\dfrac{m}{v}\\\Rightarrow v=\dfrac{m}{\rho}\\\Rightarrow v=\dfrac{41.4}{1}\\\Rightarrow v=41.4\ cm^3

So, volume of bone is 41.4 cm³

Average density of the bird is given by

\rho=\dfrac{45}{41.4}\\\Rightarrow \rho=1.08695\ g/cm^3

The average density is 1.08695 g/cm³

3 0
3 years ago
Other questions:
  • you push a coin across a table the coin stops how does this motion relate to balanced and unbalanced forces
    7·1 answer
  • When the Net Force quadrupled from 50N to 200N, how many times bigger was the acceleration?
    13·1 answer
  • When a sound wave travels through air, how is this air affected by its passage
    14·1 answer
  • Geoff was charging his phone and wanted to know how many amperes were entering his phone. What was Geoff trying to measure? A. l
    11·1 answer
  • The slope of a position-time graph can be used to find the moving object’s
    15·1 answer
  • The length and width of a rectangle are 1.82 cm and 1.5 cm respectively. Calculate area of the rectangle and write in correct si
    10·1 answer
  • 7. A pool cue ball moving at 2.1 m/s east collides in a straight line with the eight ball at rest. Find the velocity of the eigh
    7·2 answers
  • Do Earth’s oceans gain or lose water, considering evaporation and precipitation together? How much?
    10·1 answer
  • OC: Dog owner plays with the puppy when it bites, it bites more often.
    9·1 answer
  • How many meters across is a road sign that has an angular size of 120 arcseconds and is 1 km away?
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!