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Frozen_Mind
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1. The problem statement
1) A train whistle has a frequency of 1000 Hz. If the train is speeding
at a velocity of 60 km/h past a stationary railroad crossing
attendant, what is the apparent frequency a) as the train approaches him, b) as it moves away from him?
Assume speed of sound to be 350 m/s.
2) A second train is approaching the first train (above) with a speed of
60 km/h. Obtain the frequency of the whistle of the first as heard by
the engineer of the second train.
3) Sound is reflected by a screen moving with a speed 20 km/h toward
the source and observer. If the frequency of the source is 450 khz,
what is the apparent frequency of the reflected sound?
f2 = f1Vs/(Vs + or - Vo), f2 = f1(1 + or - Vo/Vs)
meh I'm really not that quite sure :S
I could calculate number 1 using the doppler effect equation f2 = f1Vs/(Vs + or - Vo), but I'm not quite sure how to solve for number 2 and 3... help please ?
1) A train whistle has a frequency of 1000 Hz. If the train is speeding
at a velocity of 60 km/h past a stationary railroad crossing
attendant, what is the apparent frequency a) as the train approaches him, b) as it moves away from him?
Assume speed of sound to be 350 m/s.
2) A second train is approaching the first train (above) with a speed of
60 km/h. Obtain the frequency of the whistle of the first as heard by
the engineer of the second train.
3) Sound is reflected by a screen moving with a speed 20 km/h toward
the source and observer. If the frequency of the source is 450 khz,
what is the apparent frequency of the reflected sound?
Homework Equations
f2 = f1Vs/(Vs + or - Vo), f2 = f1(1 + or - Vo/Vs)
meh I'm really not that quite sure :S
The Attempt at a Solution
I could calculate number 1 using the doppler effect equation f2 = f1Vs/(Vs + or - Vo), but I'm not quite sure how to solve for number 2 and 3... help please ?