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Q6.

Expert-verified
Found in: Page 43

### Physics Principles with Applications

Book edition 7th
Author(s) Douglas C. Giancoli
Pages 978 pages
ISBN 978-0321625922

# According to the rule of thumb, every five seconds between a lightning flash and the following thunder gives the distance to the flash in miles. (a) Assuming that the flash of light arrives in essentially no time at all, estimate the speed of the sound in m/s from this rule. (b) What would be the rule for kilometers?

(a) The estimated value of the speed of the sound is .

(b) The rule for kilometers will be ‘every three seconds between a lightning flash and the following thunder gives the distance to the flash in kilometers.’

See the step by step solution

## Step 1. Relation between average speed, distance, and time

Given data.

There is a gap of five seconds between the lightning flash and the following thunder that gives the distance to the flash in miles.

So, the sound is traveling one mile in 5 seconds.

You know that .

## Step 2. Calculation of the estimated speed of the sound

Here, the distance traveled by the sound is 1 mile.

Now,

(a) Then,

Therefore, the estimated speed of the sound is .

## Step 3. Finding the rule for kilometers

(b) Let the sound take time to travel a distance of 1 km or 1000 m.

Then,

Therefore, the rule is ‘every three seconds between a lightning flash and the following thunder gives the distance to the flash in kilometers.’