Sound travels about 750 miles per hour. if you stand in a canyon and sound a horn, you will hear an echo. suppose it takes about 1.5 seconds to hear the echo. how far away is the canyon wall, in feet? feet now let's generalize that result. suppose it takes n seconds to hear the echo. how far away is the canyon wall, in terms of n? preview feet

1. Answer;

-825 feet (825 ft)

Explanation;

Let the canyon wall be at W feet

The speed of the sound is 750 mph

The distance will be ( 2 ×W) (because the echo is a reflected sound)

The time is 1.5 seconds

Speed = distance /time

but; 1 mile = 5280 ft and 1 hour = 3600 s

Thus;  2W/1.5 = (750 mph)× (5280 ft/1 mile) × (1h / 3600 s)

       W = 1100 × 1.5/2

           = 825 ft

2. Answer;

= 550n ft

Explanation;

Speed = Distance/time

The speed = 750 mph

Time = n seconds

Distance = 2 W

1 mile = 5280 ft , and 1 h = 3600 secs

Therefore; 2W/n = (750 mph) x (5280 ft/ 1 mile) x (1h / 3600 s)

               = 2 W/n = 1100

               = 2 W = 1100n

               W = 550n ft

Thus in terms of n the distance of the canyon from the wall is 550n ft

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2