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AP EAMCET2008PhysicsWaves and Sound

A car is moving with a speed of 72 ~km / h towards a hill. Car blows horn at a distance of 1800 ~m from the hill. If echo is heard after 10 ~s , the speed of sound (in m / s ) is

Options

  1. A300
  2. B320
  3. C340
  4. D360

Correct answer

C. 340

Step-by-step solution

The speed of the car is 72 ~km / h =72 5 18 =20 ~m / s The distance travelled by car in 10 ~s =10 20=200 ~m Hence, the distance travelled by sound in reaching the hill and coming back to the moving driver aligned & =1800+(1800-200) & =3400 ~m aligned So, the speed of sound = 3400 10 =340 ~m / s

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