Question

A man standing in a valley between two parallel mountains fires a gun and hears echo at an interval of 2 s and 3.5s. what is a) the distance between two mountains b) the location of the man with respect to the mountain.

Answer 1

speed of sound we take as: 340 m/sec

from the diagram :

distance travelled by the wave to reach the man in 2 sec will have to travel "2x" distance

so 340 = 2x/2,

x = 340 m.

Now for the mountain 2

distance to be travelled : 2(d-x)

340 = 2(d-x)/3.5

d - x = 595 m

and d = 935 m

Hope it helps....