Sound travels about 750 miles per hour

Question

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

a) Suppose it takes about 2.5 seconds to hear the echo. How far away is the canyon wall in feet?

The canyon wall is  feet away.

b) Suppose you stand 2,200 feet from the canyon wall and sound the horn. How long will it take to hear the echo?

It will take  seconds to hear the echo.

Answer 1

750 mph

1 mph = 5280 feet per 3600 seconds= 22/15 ft/s

times 750 = 22(750)/15 = 1100 feet per second

in 2.5 seconds

that's 2750 feet

= round trip distance

so divide by two

1,375 feet one way

2200 feet away will take more than 2.5 seconds

almost twice as long, so somewhere between 2.5 and 5 seconds

closer to 5, maybe 4 seconds or so

distance= speed times time

2200 = 1100s

s =2200/1100 = 2 seconds one way

double it

4 seconds round trip to hear the echo

(actual sound speed = 761.2 mph at sea level with temperature 59 degrees,

which = 1225 feet per second)