Question

a student standing between two walls shouts once.he hears the first echo after 3 seconds and the next after 5 seconds. calculate the distance between the walls.​

Answer 1

Explanation:

It took $t_1 =1.5\:\text{s}$ for the sound to reach the 1st wall and at the same time time, the same sound took $t_2 = 2.5\:\text{s}$ to reach the 2nd wall. Assuming that the sound travels at 343 m/s, then let $x_1$ be the distance of the person to the 1st wall and $x_2$ be the distance to the 2nd wall. So the distance between the walls X is

$X = x_1 + x_2 = v_st_1 + v_st_2 = v_s(t_1 + t_2)$

$\:\:\:\:\:= (343\:\text{m/s})(4.0\:\text{s}) = 1372\:\text{m}$