A gun is fired at a distance of \(4.2\text{ km}\) from a tree. If the sound is heard after \(13\text{ s}\), then the speed of sound is:
\(323.07\text{ m/s}\)
323.07 m/s is correct.
The 13 s is the time the sound takes to travel from the gun to the tree, so its speed is distance divided by time, with the distance first converted to metres.
The noise of the shot covers the distance between the gun and the tree, \(4.2\text{ km} = 4200\text{ m}\), in 13 s.
Speed = distance ÷ time \(= \dfrac{4200}{13} \approx 323.07\text{ m/s}\).
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