Question

A train moving with velocity 30 ms^-1 blows a whistle of frequency 516 Hz. Find the pitch of the sound heard by a passenger in another train approaching the first at a speed of 15 ms^-1 , the velocity of sound = 330 ms^-1.

Answer 1

It both the trains are approaching each other. 

The apparent frequency, \(n' = (\frac{v + v_0}{v - v_s})\,n\)

\(n' = (\frac{330 + 15}{330 - 30}) \times 516\)

\(n = \frac{345}{300} \times 516 = 1.15 \times 516\)

\(n'\) = 593.4 Hz