# Physics homework without SHOUTING

Airplanes are noisy things. For example, if you stand really close to a runway, a military jet can produce a sound intensity of about $$100\text{ W/m}^2$$ at a distance of 30 m from the plane (this is beyond painful noise). You live near a military airport and want to work on physics with your friend. Since you don't want to shout, you decide to find a spot far enough away from the airport that the airplane noise is below the threshold of conversation $$(10^{-6}\text{ W/m}^2)$$. How far do you need to go from the airport in kilometers to accomplish this?

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