Question

A mirror faces a cliff, located some distance away. Mounted onthe cliff is a second mirror, directly opposite the first mirrorand facing toward it. A gun is fired very close to the firstmirror. The speed of sound is 342 m/s.How many times does the flash of the gunshot travel the round-tripdistance between the mirrors before the echo of the gunshot isheard?

Answer 1

To develop this problem, we simply have to make a relationship between speeds. This is because the echo of the sound is traveling a distance equal to that which the light travels.

We must calculate how much is that relationship of round trips between the two, as well

$N = \frac{c}{s}$

Where

c = Speed of light

s = Speed of sound

By definition we know that

$c = 3*10^8m/s$

$s = 342,2m/s$(Normal conditions)

Then,

$N = \frac{3*10^8m/s}{342,2m/s}$

$N = 876680.3$

Therefore the flash of the gunshot travel the round-trip distance between the mirror around to 876680.3 times before the echo of the gunshot is heard.