Question

Suppose you see a lightning flash and hear a thunder clap exactly 10 seconds later. The speed of sound is 1080 feet per second and there are 5280 feet in a mile. Estimate, to the nearest half mile, how many miles you are from the lightning flash. Assume the speed of light is infinite.

Answer 1

`\approx 2\ miles`

Explanation:

Difference of 10 seconds between the lightning flash and its thunder clap.

Given that the speed of light is infinite.

So, lightning will be seen at the same time it happens.

10 seconds is the time taken by the sound to reach to the person.

Time taken = 10 seconds

Speed of sound = 1080 ft/sec

To find:

Distance from lightning flash in miles.

Solution:

First of all, let us a have a look at the formula:

`Distance = Speed * Time`

Putting the given values:

Distance =
`1080* 10 = 108000\ feet`

5280 feet = 1 mile

1 feet =
`(1)/(5280)` miles

10800 feet =
`(1)/(5280)* 10800 \approx 2\ miles`