Antonio is standing on a at the edge of a canyon. He yells loudly and hears an echo 1.2 s later. How far away is the other side of the canyon? You may assume the speed of sound is 340 m/s.

Russell is watching a thunderstorm. He hears the thunder 5 s after seeing a flash of lightning. How far away was the lightning?

204 m 1700 m

Step-by-step explanation:

a) In 1.2 seconds, sound will travel a distance of ...

(1.2 s) (340 m/s) = 408 m

This is the round-trip distance, so the reflecting surface is half that distance away.

The other side of the canyon is 204 m away.

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b) In 5 seconds, the sound will travel a distance of ...

(5 s) (340 m/s) = 1700 m

This is the one-way distance, so the lightning is about 1700 m away.