Question

A hiker shouts toward a vertical cliff 685 m away. The echo is

heard 4.00 s later. What is the speed of the sound in this air?
a 253.6 m/s
b 423.8 m/s
c 342.5 m/s

Answer 1

c

Step-by-step explanation:

The time it takes for the sound to travel from the hiker to the cliff and back is equal to twice the time it takes the sound to travel from the hiker to the cliff:

t(total) = 2 * t(one way)

We know that the total time is 4.00 s, so:

4.00 s = 2 * t(one way)

t(one way) = 2.00 s

Using the formula for the speed of sound:

speed = distance / time

we can calculate the speed of sound in air as follows:

speed = distance / time(one way) = 685 m / 2.00 s = 342.5 m/s (to three significant figures)

Therefore, the speed of sound in this air is approximately 342.5 m/s. The correct answer is (c).