Question

A person stands in between two walls and claps his hands. He hears two successive echoes at a time interval of 0.00009 sec. If the distance between the two walls is 'g' and the speed of sound in air is 'k', locate the position of the person.

Answer 1

Answer:

For the first echo, sound will have to travel a distance of 2x

1

For the second echo, sound will have to travel a distance of 2x

2

For the third echo, sound will have to travel a distance of 2x

1

+2x

2

And then the process will repeat, since interval is 1 second

v

2x

2

−2x

1

=1 and,

v

2x

2

+2x

1

−2x

2

=1

Solving the equations we get, x

1

=170m and x

2

=340m

So total distance between cliffs = 510m