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The sound of an explosion on the surface of lake is heard by a boatman 100m away and a driver 100m below the point of explosion.(i) explain who will hear the sound of explosion first(ii) if the sound takes t s to reach the man how much time will it take to reach the driver? (speed of sound in air = 344 m/sspeed of sound in water = 1533 m/s ) |
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Answer» For the boatman above the surface of water... SPEED of sound in air = 344 m/s distance COVERED = 100 m time TAKEN by sound = t sec velocity = distance / time 344 = 100 / t t = 100 / 344 t = 0.29 sec Now, for the man below the surface of water speed of sound in water = 1533 m/s distance covered = 100 m time taken = t But velocity = distance / time 1533 = 100 / t t = 100 / 1533 t = 0.06 sec So , the man under the water HEAR the sound of the EXPLOSION first.... |
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