PHYSICS · Single correct · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics
Problem
An ambulance siren has a rest frequency of 500 Hz. The ambulance drives past a stationary observer at a constant speed of 30 m/s on a day when the speed of sound in air is 340 m/s. What is the frequency heard by the observer just before the ambulance reaches her?
(a) 545 Hz
(b) 550 Hz
(c) 460 Hz
(d) 500 Hz