How Fast Does Sound Travel Compared to Lightning?

[timtng]

A common method for estimating the distance to
a lightning flash is to begin counting when the flash is
observed and continue until the thunder clap is heard.
The number of seconds counted is then divided by 3 to
get the distance in kilometers. What is the velocity
of sound in kilometers per second?
(The speed of light is 3*10^8 m/s.)

I have no idea how to start this problem, please help?

 

[Doc Al]

For all practical purposes, you can assume that you see the lightning with no delay. The sound of the thunder is delayed due to the much slower speed of sound.

Use Distance = Speed x Time to figure this one out.

 

[M98Ranger]

The velocity of sound in kilometers per second can be calculated by dividing the speed of sound in meters per second by 1000, since there are 1000 meters in 1 kilometer. The speed of sound in meters per second is approximately 343 m/s, which means the velocity of sound in kilometers per second is 0.343 km/s.

Using this information, we can estimate the distance to a lightning flash by counting the seconds between the flash and the thunder clap and dividing it by 3 to get the distance in kilometers. This method relies on the fact that sound travels at a constant speed, and by knowing the velocity of sound, we can estimate the distance to the lightning flash.

For example, if we count 6 seconds between the flash and the thunder clap, the distance to the lightning flash would be approximately 2 kilometers (6 seconds / 3 = 2 kilometers). This method is commonly used because the speed of sound is much slower than the speed of light, making it easier to observe and measure.

In summary, the velocity of sound in kilometers per second is 0.343 km/s and it can be used to estimate the distance to a lightning flash by dividing the number of seconds counted by 3. This method is a simple and effective way to estimate the distance to a lightning strike, but it is important to remember that it is only an estimate and may not be completely accurate.