Question

Review: The Doppler Effect equation in general: where "s" represents the sound SOURCE, "f" is the intrinsic frequency of the sound source, and "v" is the SPEED of the source relative to air. Learning Goal: Doppler Effect - In general Self Assessment "o" represents the "OBSERVER", "f" is the frequency heard by the observer, and "v" is the SPEED of the observer relative to air. Two train whistles, A and B, each have a built-in frequency of 700 Hz. A is stationary and B is moving to the right at a speed of 35.1 m/s. A listener is between the two whistles. The speed of sound in air is 343 m/s. "v" is the speed of sound in air, v = 343 m/s. The problem solving boils down to choosing a sign in the numerator and/or choosing a sign in the denominator, as shown in: The Doppler effect in general: Observer moving at speed v (relative to medium) Source moving at speed v (relative to medium) Frequency perceived by observer: 1 Case 1: the listener moves to the RIGHT at a speed of 32.8 m/s Case 2: the listener moves to the LEFT at a speed of 32.8 m/s Case 1 ≠ 0 d source (higher /) away from source (lower /) Denominator - if source moves toward observer (higher /), if source moves away from observer (lower /) Part A - Case 1: Calculate the frequency of the whistle A heard by you Case 2 ≠ 0 Part B - Case 1: Calculate the frequency of the whistle B heard by you. Part C - Case 2: Calculate the frequency of the whistle A heard by you. Part D - Case 2: Calculate the frequency of the whistle B heard by you.

Review:
The Doppler Effect equation in general:
where "s" represents the sound SOURCE, "f" is the intrinsic frequency of the sound source, and "v" is the SPEED of the source relative to air.

Learning Goal: Doppler Effect - In general Self Assessment
"o" represents the "OBSERVER", "f" is the frequency heard by the observer, and "v" is the SPEED of the observer relative to air.

Two train whistles, A and B, each have a built-in frequency of 700 Hz. A is stationary and B is moving to the right at a speed of 35.1 m/s. A listener is between the two whistles. The speed of sound in air is 343 m/s.

"v" is the speed of sound in air, v = 343 m/s. The problem solving boils down to choosing a sign in the numerator and/or choosing a sign in the denominator, as shown in:

The Doppler effect in general:
Observer moving at speed v (relative to medium)
Source moving at speed v (relative to medium)
Frequency perceived by observer: 1

Case 1: the listener moves to the RIGHT at a speed of 32.8 m/s
Case 2: the listener moves to the LEFT at a speed of 32.8 m/s

Case 1 ≠ 0
d source (higher /) away from source (lower /)
Denominator - if source moves toward observer (higher /), if source moves away from observer (lower /)

Part A - Case 1: Calculate the frequency of the whistle A heard by you
Case 2 ≠ 0

Part B - Case 1: Calculate the frequency of the whistle B heard by you.

Part C - Case 2: Calculate the frequency of the whistle A heard by you.

Part D - Case 2: Calculate the frequency of the whistle B heard by you.