1 6 6

: .. Sound Waves

  1. #1

    Jul 2011
    -
    936

    .. Sound Waves

    Sound source observer .
    .
    vs
    ȡ (a) vs (b).


    (a)
    f T.
    T = 1/f


    (b) vs
    1 T ds vs T.



  2. #2

    Jul 2011
    -
    936

    : .. Sound Waves

    d vT v . ds vsT vs . (a) (b) :
    l'= d - ds
    l'= l - vs T

    l'= l - vs l/v

    vs.
    :
    :


    source moving toward stationary observervs < v therefore f` > f
    source moving away from stationary observervs < v therefore f` < f

  3. #3

    Jul 2011
    -
    936

    : .. Sound Waves

    For Example
    If source emits a sound of frequency 400Hz when at rest, then when the source moves toward a fixed observer with speed of 30m/s, the observer hear a frequency of

    In the case of the source moves away from a fixed observer with speed of 30m/s, the observer hear a frequency of
    vs
    :


    v` = v + vo

    v` = v - vo
    vo v





    observer moving toward stationary sourcef` > f
    observer moving away from stationary sourcef` < f
    Example
    The siren of a police car at rest emits at a predominant frequency of 1600Hz. What frequency will you hear if you are at rest and the police car moves at 250m/s (a) toward you, (b) away from you?

    Solution
    (a)



    (b)



    Example
    A 5000Hz sound wave is directed toward an object moving 3.5m/s toward the stationary source. What is the frequency of the reflected wave?

    Solution
    () . ( ).

    First case when the observer moves toward the sound source



    Second case when the car reflect the sound toward the observer

    f 5051Hz


    Beats . . .

  4. #4

    Jul 2011
    -
    716

    : .. Sound Waves


  5. #5

    Aug 2011
    Jordan - Zerqa
    902

    : .. Sound Waves



  6. #6

    Jul 2012
    5,302

    : .. Sound Waves



: 1 (0 1 )