# physics

posted by
**tim**
.

You let out a shout, echo comes back and reaches you in 1.4 seconds. if the speed of sound in air is 343 m/s, what is the distance to the cliff?

a. need assitance in setting up problem?

Let d be the distance to the cliff, and V be the speed of sound. The sound must travel a distance 2 d to hear the echo.

2d = V t

Solve for the distance d and substitute the numerical values of t and V.

i was wondering where the 2 came from?

The sound of an echo must make a round trip to the reflecting wall and back. The shouter is also the listener. That's why the 2 is there

s=d/t

you have t and s and want to find d - algebra allows yoy to re-write the equation - be aure to use units in your answer - former teacher