# A train running at 108 km h-1 towards east whistles at a dominant frequency

Question:

A train running at $108 \mathrm{~km} \mathrm{~h}^{-1}$ towards east whistles at a dominant frequency of $500 \mathrm{~Hz}$. Speed of sound in air is $340 \mathrm{~m} / \mathrm{s}$. What frequency will a passenger sitting near the open window hear? (b) What frequency will a person standing near the track hear whom the train has just passed? (c) A wind starts blowing towards east at a speed of $36 \mathrm{~km} \mathrm{~h}^{-1}$. Calculate the frequencies heard by the passenger in the train and by the person standing near the track.

Solution: