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BITSAT2023PhysicsMotion in One DimensionActual

A passenger sitting in a train A moving at 90 ~km /h observes another train B moving in the opposite direction for 8 ~s . If the velocity of the train B is 54 ~km / h , then length of train B is :

Options

  1. A80 ~m
  2. B200 ~m
  3. C120 ~m
  4. D320 ~m

Correct answer

D. 320 ~m

Step-by-step solution

Velocity of train A ( V _ A =90 km hr =90 5 18 =25 ~m / s ) Velocity of train B ( V _ B =54 km hr =54 5 18 =15 ~m / s ) Velocity of train B w.r.t. train ( aligned A= V _B & - V _A & =15-(-25) m / s & =40 ~m / s aligned ) Time of crossing (= length of train relative velocity ) ((8)= 40 ) ( =8 40=320 ) meter.

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