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Paragraph: Two trains A and B are moving with speeds 20 ~m / s and 30 ~m / s , respectively in the same direction on the same straight track, with B ahead of A . The engines are at the front ends. The engine of train A blows a long whistle. Assume that the sound of the whistle is composed of components varying in frequency from f₁=800 ~Hz to f₂=1120 ~Hz , as shown in the figure. The spread in the frequency (highest f

Options

  1. A340 ~m / s for passengers in A and 310 ~m / s for passengers in B
  2. B360 ~m / s for passengers in A and 310 ~m / s for passengers in B
  3. C310 ~m / s for passengers in A and 360 ~m / s for passengers in B
  4. D340 ~m / s for passengers in both the trains

Correct answer

B. 360 ~m / s for passengers in A and 310 ~m / s for passengers in B

Step-by-step solution

v_ S A =340+20=360 ~m / s v_ S B =340-30=310 ~m / s Therefore, correct option is (b).

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