Task 3:
a)
The Doppler effect is a phenomenon in physics that describes the change in frequency of
a wave, such as light or sound. For example, when a sound source approaches, the
perceived frequency of the sound increases thus creating a higher pitch while when the
sound moves away, the perceived frequency decreases, causing a lower pitch noise. A
perfect example of this is an ambulance siren moving towards and away from the person
experiencing the Doppler effect. Another application of the Doppler effect would be
phone calls. For example, when moving away or towards a cell tower, the frequency of
radio waves processing our voice and data changes.
b)
Given: F source = 400hz, vsource = 20m/s T = 10 degrees C
Unknown = f observed v sound
Equation = V sound = 332m/s + (0.59m/s) T
f observed = f source (
??????
?????? + ???????
)
V sound = 332 m/s + (0.59m/s)10
V sound = 332 m/s + 5.9m/s
V sound = 337.9m/s
Therefore V sound = 337.9m/s in a 10-degree Celsius room
f observed = 400 (
377.9?/?
337.9?/? + 20?/?
)
F observed = 400(0.94m/s)
F observed = 377.6473hz
F observed = 378hz
Therefore moving away frequency observed = 378hz
F observed = 400 (
377.9?/?
337.9?/? − 20?/?
)
F observed = 400 (
377.9?/?
337.9?/? − 20?/?
)
F observed = 425(1.0629)
F observed = 425.165hz
F observed = 425hz
Therefore the moving towards frequency = 425hz
