Physics · Wave motion, longitudinal and transverse waves, speed of the travelling wave, displacement relation for a progressive wave

A train is approaching towards a platform with a speed of while blowing a whistl

A train is approaching towards a platform with a speed of \( 10 m s^{-1} \) while blowing a whistle of frequency \( 340 \mathrm{Hz} \) What is the frequency of whistle heard by a stationary observer on the platform? Given speed of sound \( =340 m s^{-1} \)

  • A. зЗО н 2
  • B. 350 нz
  • C. 340 н \( z \)
  • D. 360 нz

Step-by-step solution

Using the Doppler effect formula for a source approaching a stationary observer: f' = f * v/(v - vs) = 340 * 340/(340 - 10) = 340 * 340/330 ≈ 350 Hz.
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