Question

you hear the siren from a police car and the frequency you hear is decreasing. which of the following can you conclude are plausible? group of answer choices the car is receding from you at a constant speed. the car is receding from you at an increasing speed. the car is receding from you at a decreasing speed. the car is approaching you at a constant speed. the car is approaching you at an increasing speed. the car is approaching you at a decreasing speed.

Answer 1

One must conclude that the distance between wavefronts emitted (and received) is increasing

That rules out a siren moving at constant speed

Only a car receding from you at increasing speed or a car approaching you at decreasing speed can account for the increase in distance between wavefronts emitted