Question

(1) Suppose an oncoming ambulance moving at 115 km/h emits a steady 810-Hz sound from its siren.

**Part (a)** What frequency, in Hz, is received by
a person watching the oncoming ambulance? The speed of sound on
this day is 345 m/s.

**Part (b)** What frequency, in Hz, does she
observe after the ambulance has passed?

(2). In this problem take the speed of sound to be 349 m/s.

How fast, in meters per second, does an observer need to approach a stationary sound source in order to observe a 4.5 % increase in the emitted frequency?

Answer #1

What frequency (in Hz) is received by a person watching an
oncoming ambulance moving at 118 km/h and emitting a steady 850 Hz
sound from its siren? The speed of sound on this day is 345
m/s.
What frequency (in Hz) does she receive after the ambulance has
passed? Hz

(a)
What frequency (in Hz) is received by a person watching an
oncoming ambulance moving at 106 km/h and emitting a steady 850 Hz
sound from its siren? The speed of sound on this day is 345
m/s.
Hz
(b)
What frequency (in Hz) does she receive after the ambulance has
passed?
Hz

The siren on an ambulance is emitting a sound whose frequency is
2550 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
26.2 m/s. Determine the wavelength and the frequency of the sound
you hear. (c) If the ambulance is...

The siren on an ambulance is emitting a sound whose frequency is
2450 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
26.8 m/s. Determine the wavelength and the frequency of the sound
you hear. (c) If the ambulance is...

The fire engine siren emits a 750 Hz sound as travels at 85
km/hr. Calculate the frequencies heard by a stationary observer as
the fire engine approaches and then travels away from the
observer.

The frequency will sound different if we hear a sound source
moving relative to us. This phenomenon is called the Doppler Effect
in Physics. An ambulance sounds a siren at 1515 Hz and passes a
cyclist moving at 2.12 m / s. After the ambulance passed, the
cyclist heard a siren sound at a frequency of 1501 Hz. The speed of
sound in the air is about 343 m / s.
What is the speed (speed) of the ambulance in...

An ambulance with a 200-Hz siren is moving at 30.0 m/s. Take the
speed of sound to be 340 m/s. a) What frequencies are observed by a
stationary person standing on the sidewalk as the ambulance
approaches and after it passes? b) Is this Doppler shift real or
just a sensory illusion?

An ambulance is traveling East at 20m/s. The siren emits a fixed
frequency of 240Hz. Each of the following cars is traveling down
the road as described. Rank the cars according to the frequency the
driver will hear. Select 1 for the car which will hear the highest
frequency. Remember that if the frequency is the same, select the
same rank and skip the next number. I really suggest drawing a
picture to help sort this out. Keep in mind...

An ambulance is traveling East at 20m/s. The siren emits a fixed
frequency of 270Hz. Each of the following cars is traveling down
the road as described. Determine if the driver of the car will hear
a frequency the same as 270Hz, higher than 270Hz, or lower than
270Hz.
A)A car driving East at a speed of 20m/s. The car is in front of
the ambulance.
B)A car driving East at a speed of 15m/s. The car is behind the...

A. What is the intensity in 10-4 watts per meter
squared of 112 dB sound?
B.A spectator at a parade receives an 886 Hz tone from an
oncoming trumpeter who is playing an 863 Hz note. At what speed is
the musician approaching if the speed of sound is 336 m/s?
C. What frequency is received by a person watching an ambulance
moving away at 89 km/h and emitting a steady 774 Hz sound from its
siren? The speed of...

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