a car moving at 25 m/s approaches a stationary whistle that emits a 350 Hz sound

a) velocity of Listener, VL = 25 m/s velocity of sound, vo = 343 m/s now Apply Doppler's effect a) f' = f*(vo+VL)/Vo =350*(343+25)/343 = 375.5 Hz

ID: 1387406 • Letter: A

Question

a car moving at 25 m/s approaches a stationary whistle that emits a 350 Hz sound. the soeed of sound in the air is 343 m/s.

a. what is frequency of sound heard by driver?

b.. what is frequency of sound heard by driver of the car after passing the whistle and moving away from it?

c. what is frequency of sound heard by driver of the car if the whistle is also moving toward the car with a speed of 12 m/s?

d. what is frequency of sound heard by driver of the car of the whistle is now moving in same direction of the car with speed of 12 m/s?

a) velocity of Listener, VL = 25 m/s

velocity of sound, vo = 343 m/s

now Apply Doppler's effect
a)

f' = f*(vo+VL)/Vo

=350*(343+25)/343

= 375.5 Hz <<<<<<---------Answer

b)
f' = f*(vo - VL)/Vo

=350*(343-25)/343

= 324.5 Hz <<<<<<---------Answer

c) velocity of source, Vs = 12 m/s

f' = f*(vo+VL)/(Vo-Vs)

=350*(343+25)/(343-12)

= 389.1 Hz <<<<<<---------Answer

b)
f' = f*(vo - VL)/(Vo +Vs)

=350*(343-25)/(343 + 12)

= 313.5 Hz <<<<<<---------Answer

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