Page 62 - Q & A STPM 2022 Physics

Physics Semester 3 STPM Chapter 21 Sound Waves
(e) (i) The ambulance (source) is approaching the car (observer), and the
car is moving away from the ambulance.
u = 42.0 m s –1 u = 25.0 m s –1
s o

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Frequency heard, f 1 =  330 – 25.0  (500 Hz) = 530 Hz
330 – 42.0

(ii) The ambulance (source) is now moving away from the car (observer),
and the car is approaching the ambulance.

u = 25.0 m s –1 u = 42.0 m s –1
s
0

Frequency heard, f 1 =  330 + 25.0  (500 Hz) = 477 Hz
330 + 42.0

Semester
3

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021 STPM Q&A Physics T3.indd 422 17/02/2022 10:24 AM