Question

A truck travel down a highway at a speed of 66m/s with it's horns emitting sound at a frequency of 800Hz . What frequency is heard by a passenger in a car traveling at 60m/s in the same direction,as the car and truck approach each other (take velocity of sound in air as 350m/s)

Answer 1

According to the Doppler effect, the frequency heard by a passenger will be

$\displaystyle \nu = \nu_0 \frac{c+v_{obs}}{c-v_{source}} = 800 \frac{350 +60}{350-66} = 1155 \; Hz$

Answer: 1155 Hz