Question

A man stands in between two high raised building & blows a whistle.He hears two successive echos after 0.8 sec & 2.4sec
.Calculate the distance between the buildings .
(Speed of sound = 330 m/s)

Answer with full explanations .....

Answer 1

we know ,
time taken in echo sound = 2 x distance of source from building /speed of sound

0.8 = 2 x distance of source from 1st building /330

330 x 0.8/2 = distance of source from 1st building

132 m= distance of source from 1st building.

in the same way ,
distance of source from 2nd building =330 x 1.2 = 396 m

now distance between buildings = distance of source from 2nd building + distance of source from qst building = 396 +132 =528 m

Answer 2

Let the distance between the man and the first building be x m
time = 0.8 sec
speed = 330 m/s
distance = 2x

Distance = speed × time
= 330×0.8
= 264 m

x = 132 m

Similarly let the distance between the man and the 2nd building be y m
time = 2.4 sec
Speed = 330 m/s
Distance = 2y

Distance = speed × time
= 330 × 2.4
= 792 m

y = 396 m
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Therefore the distance between the two buildings = x+y
= 132 + 396
= 528 m
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