A person on a railroad car blows a trumpet sounding at 485.0 Hz. The car is moving toward a wall at 21.0 m/s. assume the speed of sound is 343.0 m/s
Calculate the frequency of the sound as received at the wall.
Calculate the frequency of the reflected sound arriving back at the source.
Calculate the frequency of the sound as received at the wall.
Calculate the frequency of the reflected sound arriving back at the source.

case 1 :
Using DOPLER effect equation F'=[( VVo) / (VVs)] (f)
HERE Vo=velocity of observer , Vs=velocity of source, V=343 m/s and f=FREQ of trumpet.
here Vo=0, Vs=21 m/s
so F'={ (3430) / (34321) ](485)
= 516.6 Hz
Case 2:
HERE weve to consider the source as wall and the car as observe as reflected sound is heard by car.
source freq=reflected wall freq= 516.6 (from case1)
so F''=[ (VVo) / (VVs) ](516.6)
substituting F''=[ (343(21)) / (3430)] (516.6)
=548.22 HZ
Using DOPLER effect equation F'=[( VVo) / (VVs)] (f)
HERE Vo=velocity of observer , Vs=velocity of source, V=343 m/s and f=FREQ of trumpet.
here Vo=0, Vs=21 m/s
so F'={ (3430) / (34321) ](485)
= 516.6 Hz
Case 2:
HERE weve to consider the source as wall and the car as observe as reflected sound is heard by car.
source freq=reflected wall freq= 516.6 (from case1)
so F''=[ (VVo) / (VVs) ](516.6)
substituting F''=[ (343(21)) / (3430)] (516.6)
=548.22 HZ

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