The horn of a car emits sound with a dominant frequency of 2400 Hz. What will be the apparent dominant frequency heard by a person standing on the road in front of the car if the car is approaching at `18.0 km h^-1`? Speed of sound in air` = 340 m s^-1`

Answer

B, C, D

Explanation

`f_1=((u+v_m-v_0)/(v+v_m-v_s))F`
[1km/h=5m/s]
using sign conventions
App frequency `=((340+0-0)/(340+0-5))xx2400`
`=2436Hz`