Two engines pass each other in opposite directions with a velocity of `60 kmh^-1` each. One of them is emitting a note of frequency 540. Calculate the frequencies heard in the other engine before and after they have passed each other. Given velocity of sound = `316.67 ms^-1`.

Two engines pass each other moving in opposite directions with uniform speed of of them is blowing a whistle of frequency 540 Hz. Calculate the frequency heard by driver of second engine before they pass each other. Speed of sound is 300 m/sec :

Two cars are approaching each other on a straight road and moving with a velocity of 30 kmh-1 . If the sound produced in a car is of frequency 500 Hz, what will be the frequency of sound as heard by the person sitting in the other car ? When the two cars have crossed each other and are moving away from each other, what will be the frequency of sound as heard by the same person ? Speed of sound= 330 ms^-1 .

Two cars are moving towards each other with equal speed of 72 km h^(-1) . First car is emitting continuously a note of frequency 512 Hz. Find the apparent pitch heard by a person in 2^(nd) car before and after they cross each other. (Speed of sound = 340 m/s)

Two trains, each 50 m long, are travelling in opposite directions with velocities 10 ms^-1 and 15 ms^-1 . The time of their crossing each other is.

Two aeroplanes A and B are approaching each other and their velocities are 108 kmh^(-1) and 144 kmh^(-1) respectively. The frequency of a note emitted by A as heard by the passangers in B is 1170 Hz. Calculate the frequency of the note heard by the passangers in A. Velocity of sound = 350 ms^(-1) .

Two express trains moving at 100 kilometre per hour are travelling towards each other while one of them is whistling continuously. If the frequency of the note is 1000 Hz, find the apparent pitch to an observer in the other train (a) before the trains pass by each other and (b) after they have passed each other. (Velocity of sound in air = 340 m//s )