Problem Solving: Sound travels about 750 miles per hour. If you stand in a canyon and sound a horn, you will hear an echo.

Question

Suppose it takes about 3 seconds to hear the echo. How far away is the canyon wall, in feet? ___ft

Answer 1

To hear the echo, the sound will have had to gone out to the wall and returned to you. The sound's speed, in feet/second is:

(750 mi/hour)*(1 hour/3600 seconds)*(5280 feet/mile) = 1100 ft/sec

In 3 seconds, the sound will have traveled 3300 feet. Since the sound's movement is a round trip, the canyon wall is 3300/2 = 1650 feet away.

Answer 2

To hear the echo, the sound will have had to gone out to the wall and returned to you. The sound's speed, in feet/second is:

(750 mi/hour)*(1 hour/3600 seconds)*(5280 feet/mile) = 1100 ft/sec

In 3 seconds, the sound will have traveled 3300 feet. Since the sound's movement is a round trip, the canyon wall is 3300/2 = 1650 feet away.