A train is moving on a straight track with speed 20 m s^(-1) . It is blowing its whistle at the frequency of 1000 Hz. The percentage change in the…

Question

A train is moving on a straight track with speed 20 m s^(-1) . It is blowing its whistle at the frequency of 1000 Hz. The percentage change in the frequency heard by a person standing near the track as the train passes him is (speed of sound =320 m s^(-1) ) close to:

MARKS Content Team · Accepted Answer

Correct answer: (C) 12%. Before train passes f^(′)=v/(v-v_s)×f_0 =320/(320-20)×f_0 =320/300×f_0 =16f_0/15 After train passes f^(′′)=v/(v+v_s)×f_0 f^(′′)=320/(320+20)f_0 =320/340f_0 =16/17f_0 Change in frequency =16/15-16/17f_0 ∴ Percentage change in frequency =16/15-16/17f_0f_0×100 ≈12% nearly

A train is moving on a straight track with speed $20 m s^{- 1}$ . It is blowing its whistle at the frequency of $1000 Hz$ . The percentage change in the frequency heard by a person standing near the track as the train passes him is (speed of sound $= 320 m s^{- 1}$ ) close to:

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Relevant Questions

A train is moving on a straight track with speed 20 m s-1 . It is blowing its whistle at the frequency of 1000 Hz. The percentage change in the frequency heard by a person standing near the track as the train passes him is (speed of sound =320 m s-1 ) close to:

Solution

Relevant Questions

A train is moving on a straight track with speed $20 m s^{- 1}$ . It is blowing its whistle at the frequency of $1000 Hz$ . The percentage change in the frequency heard by a person standing near the track as the train passes him is (speed of sound $= 320 m s^{- 1}$ ) close to: