A person hears a mountain echo 6 s after clapping. Sound speed is 343 m s⁻¹. Find mountain distance.

Solution & explanation

1. Given: v = 343 m s⁻¹; round-trip t = 6 s.

2. The sound travels to the reflector and returns.

   $$2\times d=t\times v$$

3. Divide both sides by two.

   $$d=\frac{t\times v}{2}$$

4. Substitute the supplied speed and delay.

   $$d=\frac{2058}{2}$$

5. Calculate the complete round-trip distance.

   $$s=343\times 6=2058$$

6. Take half for one-way distance.

   $$d=\frac{2058}{2}=1029.0$$

7. State the result with units: d = 1029 m.

d = 1029 m