Q:

Una ambulancia se desplaza hacia el norte a 23,5 m/s. Su sirena emite un sonido de 500Hz de frecuencia. Calcular la frecuencia aparente que percibe un observador que viaja en su auto, también hacia el norte , a 28,6, cuando:

Accepted Solution

A:
Answer: (I attach your complete question in the picture below)The apparent frequency would be  f' = 493.26 Hz Step-by-step explanation: This a Doppler's effect problem. This effects produces a slight change in the frequency of a traveling wave, due to the effect of the velocity of the receiver (observer). The formula used to describe the change, as both vehicles are moving away of each other: f' = [ (Vwave + Vobserver) / (Vwave + Vsource ) ]*f Where  Vwave = 340 m/s ( speed of sound) Vobserver = 18.6 m/s (observer = car) Vsource = 23.5 m/s (speed of the ambulance = source) f = 500 Hz (frequency of the sound) We just need to substitute in the equation f' = [(340+ 18.6) / (340+ 23.5)] * 500 Hz f' = [0.9865] * 500 Hz = 493.26 Hz f' = 493.26 Hz