Question

An echo is heard from a building 0.485 s after you shout "hello." How many feet away is the building if the air temperature is 30.6°C?

Answer 1

Answer: 84.63 m

Step-by-step explanation:

The speed of sound in the air, at
`0 \°C` is
`331.5 m/s`, and for each degree Celsius the temperature rises, the speed of the sound increases by
`0.6 m/s`. So, if we estimate the speed of sound at
`30 \°C` it will be
`349 m/s`.

On the other hand, the speed of sound
`V` is defined as the distance traveled
`d` in a especific time
`t`:

`V=(d)/(t)`

Where:

`V=349 m/s` is the speed of sound

`t=(0.485 s)/(2)=0.2425 s` is half the time the sound wave travels since you say "hello", the sound wave hits the building and then returns to you

`d` is the distance between you and the building

`349 m/s=(d)/(0.2425 s)`

Finding
`d`:

`d=(349 m/s)(0.2425 s)`

Finally:

`d=84.63 m`