1© Manhattan Press (H.K.) Ltd. Source moving Observer moving Observer moving 11.5 Doppler effect Both source and observer moving Both source and observer.

Slides:



Advertisements
Similar presentations
Doppler Effect Introduction In our everyday life, we are used to perceive sound by our sense of hearing. Sounds are the vibrations that travel through.
Advertisements

Doppler Effect Liu Po Shan Memorial College Chan Yick Nam.
LECTURE 9 Ch 16.7 BEATS Ch Doppler Effect
As the police car approaches, the sound waves from its siren are compressed towards the observer. The intervals between waves diminish, which.
The velocity of sound in glycerol is m/s
Doppler Effect Moving Source.
1© Manhattan Press (H.K.) Ltd. Loudness, pitch and quality Intensity level and loudness Intensity level and loudness 11.2 Properties of sound.
Doppler Effect(1) Stationary source Stationary observer Moving source
PHY 102: Waves & Quanta Topic 5 Sound John Cockburn Room E15)
Dr. Jie ZouPHY Chapter 17 Sound Waves (cont.)
Chapter 3: Sound Wave Intensity of Periodic Sound Waves
Doppler Effect Angelourd T.Quibuyen and Ariel C. Alvarez Physics Department, Western Mindanao State University Normal Road, Baliwasan, Zamboanga City.
DOPPLER EFFECT This is the apparent change in the frequency of a wave motion as noted by an observer when there is relative motion between the source.
D OPPLER E FFECT. R ECAP FROM L AST WEEK … Intensity Level (a.k.a., loudness) Sound Intensity.
THE DOPPLER EFFECT Section 9.5. Key Terms  Doppler Effect.
The Doppler Effect.
1© Manhattan Press (H.K.) Ltd Resonance tube – Measurement of speed of sound in air.
***Doppler effect….
Doppler Effect The Doppler effect is the apparent change in the frequency of a wave motion when there is relative motion between the source of the waves.
Created by Joshua Toebbe NOHS 2015
1© Manhattan Press (H.K.) Ltd. 9.6Beats Beats (SB p. 50) Interference What is the effect of the superposition of two sound waves of slightly different.
Chapter 10: Sound Section 1: The Nature of Sound
Doppler Effect Physics 11.
1© Manhattan Press (H.K.) Ltd Stationary waves on a stretched string.
1© Manhattan Press (H.K.) Ltd Radar speed trap.
1© Manhattan Press (H.K.) Ltd Stationary waves in an open pipe.
Sound Waves  Sound is a longitudinal wave  It requires a medium to convey it, e.g. a gas, liquid, or solid  In a gas, the amplitude of the sound wave.
Doppler Effect Doppler effect- an observable change in frequency. As a moving object approaches an observer the frequency goes up, as is moves away the.
Astrophysics and Cosmology The Wavelengths get “squished” in the direction of motion, and “stretched” in the opposite direction. Doppler Shift Longer,
CHAPTER 14 Sound Doppler Effect A train passes by you with its whistle/horn blowing. You hear one pitch (tone) as the train is coming towards you and a.
Sources of Sound  sound is a mechanical wave produced by vibrations that occur in a medium-- generally air  sound is a longitudinal wave.
The Doppler Effect.
Doppler Effect Change in frequency when a source of sound is moving relative to an observer. Source of sound moving Source of sound stationary Hears lower.
Diffraction – The bending of a wave around a barrier, such as an obstacle or the edges of an opening.
Sect. 12-6: Sound Wave Interference & Beats Like any other waves, sound waves can interfere with each other. Example Can lead to beats.
 For source moving away from observer, wavelength increases  Following the same procedures gives   For source moving away, f o
1© Manhattan Press (H.K.) Ltd Stationary waves in air.
"I love hearing that lonesome wail of the train whistle as the
1 Wave Interference: Beats 2 Beats Previously we considered two interfering waves with the same . Now consider two different frequencies. When waves.
Use your imagination … … to describe what’s happening in the following audio clip.
11: Wave Phenomena 11.2 The Doppler Effect. The Doppler Effect When a car passes you on the street, the frequency of its engine note appears to change.
Doppler Effect. As a wave source approaches, an observer encounters waves with a higher frequency. As the wave source moves away, an observer encounters.
Doppler Effect David William D. Ecoben III-Archimedes.
The Doppler Effect. Shown by all types of waves Properties of Waves Waves are characterized by two numbers: Wavelength,  (size of the wave) Frequency,
The Doppler Effect The sound of a police car siren changes as it moves past you. The pitch of the siren seems to change. Ahead of the car, the sound waves.
1© Manhattan Press (H.K.) Ltd Nature of sound waves.
Physics. Wave and Sound - 5 Session Session Objectives.
Introducing Sound Waves David William D. Ecoben III-Archimedes.
Doppler Effect. Doppler Shift (p272)If there is relative motion between the source of a wave and the receiver of the wave the frequency received will.
The Doppler Effect Pg 503. Bell Ringer  What do you observe when an ambulance with a flashing siren comes towards you? Away from you? Why?
The Doppler Effect Textbook: 13.5 Homework: pg. 473 # 18, 19 pg. 476 # 64 – 71.
The Doppler Effect Introductory Video as a sound source moves towards you it appears to have a higher frequency than normal as the source moves away it.
Today (Finish Chapter 13, Sound)  Temperature and Heat Concepts Tomorrow (Start Chapter 14)  Standing Waves  Beats  Doppler Effect  Example Problems.
Sound and the Doppler Effect. Sound All sounds are produced by the vibrations of material objects They are compressional waves carried by a medium (air,
Doppler Effect A Doppler effect is experienced whenever there is relative motion between a source of waves and an observer. A Doppler effect is experienced.
Doppler effect Eeeeeee – yowwwwwwwwww A change in frequency or pitch of a sound detected by an observer.
IP Moving wave sources Moving wave sources.
Doppler Effect The Doppler effect is the apparent change in the frequency of a wave motion when there is relative motion between the source of the waves.
The Doppler Effect THE LAST LECTURE.
Doppler Effect The apparent shift in frequency caused by the movement of the sound source or the movement of the observer. When the waves get crunched.
Doppler Effect Doppler Effect – The apparent change in frequency of a wave due to the motion of the source and/or the observer Stationary Source – Moving.
1. Doppler Effect Change in frequency of a wave due to relative motion between source and observer. A sound wave frequency change is noticed as a change.
Doppler effect Eeeeeee – yowwwwwwwwww
Harmonic Motion and Mechanical Waves
11: Wave Phenomena 11.2 The Doppler Effect.
The Doppler Effect.
Doppler effect Eeeeeee – yowwwwwwwwww
Doppler Effect.
1 The Doppler shift explains
Doppler Effect.
Presentation transcript:

1© Manhattan Press (H.K.) Ltd. Source moving Observer moving Observer moving 11.5 Doppler effect Both source and observer moving Both source and observer moving

2 © Manhattan Press (H.K.) Ltd Doppler effect (SB p. 180) Doppler effect The apparent change in the pitch or frequency of a source of sound when there is relative motion between the source and the observer is known as the Doppler effect. E.g. - Siren of ambulance or police car appears to change its pitch

3 © Manhattan Press (H.K.) Ltd Doppler effect (SB p. 181) Doppler effect Image swimmer treading water Swimmer towards A (speed < wave speed) more waves (higher f) less waves (lower f)

4 © Manhattan Press (H.K.) Ltd Doppler effect (SB p. 182) Source moving 1. Source approaching observer (A) When the source is approaching the observer, the frequency encountered by the observer is higher.

5 © Manhattan Press (H.K.) Ltd Doppler effect (SB p. 183) Source moving 2. Source moving away from observer (B) When the source is moving away from the observer, the frequency encountered by the observer is lower. Go to Example 5 Example 5

6 © Manhattan Press (H.K.) Ltd Doppler effect (SB p. 184) Observer moving 1. Observer approaching a stationary source (O) Irrespective of whether the observer or the source is moving towards the other, the apparent frequency is higher.

7 © Manhattan Press (H.K.) Ltd Doppler effect (SB p. 185) Observer moving 2. Observer moving away from source (S) Irrespective of whether the observer or the source is moving away from the other, the apparent frequency is smaller. Go to Example 6 Example 6

8 © Manhattan Press (H.K.) Ltd Doppler effect (SB p. 186) Both source and observer moving Go to Example 7 Example 7 If the source and observer approach each other, the apparent frequency is higher. Conversely, the apparent frequency is lower if they are moving away from each other. uouo usus ObserverTo source+ Away from source- SourceTo observer- Away from observer+

9 © Manhattan Press (H.K.) Ltd. End

10 © Manhattan Press (H.K.) Ltd. Q: Q: The frequency of a police car siren is 400 Hz. Calculate the apparent frequency received by a stationary observer when (a) the car approaches him with a speed of 30 m s −1, and (b) the car moves away from him with a speed of 30 m s −1. (Speed of sound = 330 m s −1 ) Solution 11.5 Doppler effect (SB p. 183)

11 © Manhattan Press (H.K.) Ltd. Solution: Return to Text 11.5 Doppler effect (SB p. 183)

12 © Manhattan Press (H.K.) Ltd. Q: Q: A whistle emits sound of frequency 440 Hz. If the speed of sound is 340 m s –1, what are the frequencies of the sounds detected by an observer inside a car which is moving with a velocity of 20 m s –1 (a) towards the whistle, and (b) away from the whistle? Solution 11.5 Doppler effect (SB p. 186)

13 © Manhattan Press (H.K.) Ltd. Solution: Return to Text 11.5 Doppler effect (SB p. 186)

14 © Manhattan Press (H.K.) Ltd. Q: Q: A whistle producing sound of frequency Hz moves with a velocity of 50 m s −1. An observer also moves in the same direction with a velocity of 25 m s −1. If the speed of sound in air is 350 m s −1, what is the frequency of the sound heard by the observer? Solution 11.5 Doppler effect (SB p. 187)

15 © Manhattan Press (H.K.) Ltd. Solution: 11.5 Doppler effect (SB p. 187) Situation 1: The source is in front of the observer. Using the sign convention discussed earlier: 1. Since the observer is approaching the source, the velocity of the observer is +u o. 2. Since the source is moving away from the observer, the velocity of the source is +u s.

16 © Manhattan Press (H.K.) Ltd. Solution (cont’d): Return to Text 11.5 Doppler effect (SB p. 187) Situation 2: The source is behind the observer. 1. Since the observer is moving away from the source, hence use -u o. 2. Since the source is moving towards the observer, hence use -u s.