Doppler Effect Moving Source

Warm Up on Pear Deck High pitched sounds have relatively large _______ and small _______. As the frequency of a sound increases, the wavelength _______ and the period_______ When the frequency of a forced vibration approaches the natural frequency of a vibrating object, the vibration in the object increases its A woman standing on a train platform listens to a train as it approaches her at a constant speed. The train engineer blows the whistle of the train, which produces a frequency of 450 Hz. As the train approaches the woman on the platform, she will hear the frequency (pitch) of the whistle as

Doppler Effect Relative motion creates a change in frequency HowStuffWorks Videos "Assignment Discovery: Doppler Effect” Doppler fire engine

Doppler Effect

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Doppler Example A student sees a train that is moving away from her and sounding its whistle at a constant frequency. Compared to the sound produced by the whistle, the sound observed by the student is (1) greater in amplitude (2) a transverse wave rather than a longitudinal wave (3) higher in pitch (4) lower in pitch

Practice Choose the letter of each statement about the Doppler Effect that is true. a. It occurs when a wave source moves towards an observer. b. It occurs when an observer moves towards a wave source. c. It occurs when a wave source moves away from an observer. d. It occurs when an observer moves away from a wave source.

Practice Two fire trucks with sirens on speed towards and away from an observer as shown below. a) Which truck produces a higher than normal siren frequency? b) Which truck produces a lower than normal siren frequency?

Math Source moving towards observer fo = v•fs/(v-vs) Source moving away from observer fo=v•fs/(v+vs)

Math Practice A police car is moving toward a stationary observer at 15 m/s and its siren is sounding at 800 hz. What frequency will the observer hear is the speed of sound in 341 m/s? From the previous problem, what frequency would the observer hear after the car passes if it continues at the same speed?

Math Practice While standing near a railroad crossing, a person hears an approaching train horn at 440 Hz. The train is traveling at 20.0 m/s and the speed of sound is 346 m/s. What is the actual frequency emitted by the horn?

Math Practice - challenge problem A car approaching a stationary observer emits 450. Hz from its horn. If the observer detects a frequency of 470. Hz, how fast is the car moving? The speed of sound is 343 m/s.