Question

An ambulance car is going with a speed of 60 km/h, while a car is trying to go around it in a circle with a speed 50 km/h. If the sound that ambulance car emits has a frequency of 1 kHz, which frequency does the driver of the car hear in Hz when the ambulance car is in the center of the circle it makes, and the car makes an angle θ=30∘ with the direction of the car?