Question

An opera singer in a convertible sings a note at 700 hz while cruising down the highway at 83 km/h . the speed of sound in the air is 343 m/s. part a what is the frequency heard by a person standing beside the road in front of the car?

Answer 1

In meters per second, the singer is traveling ...

... 83 km/h × (1 h)/(3600 s) × (1000 m)/(1 km) ≈ 23 1/18 m/s

Then the observed frequency is ...

... f' = 343/(343 -23.056)·700 Hz ≈ 750.4 Hz