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fuzzy361

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**Rocket travels into space, emits sound -- intensity/time question**

## Homework Statement

A rocket, starting from rest, travels straight up with an acceleration of 56.7 m/s2. When the rocket is at a height of 722 m, it produces a sound that eventually reaches a ground-based monitoring station directly below. The sound is emitted uniformly in all directions. The monitoring station measures a sound intensity I. Later, the station measures an intensity one-third I. Assuming that the speed of sound is 343 m/s, find the time that has elapsed between the two measurements.

## Homework Equations

I= P/A

I=P/(4*pi*r^2)

## The Attempt at a Solution

I think I'm completely screwed up in the way I'm viewing this problem (by the way, I'm possibly the worst physics student ever, so please excuse the idiocy of my question). I've been assuming that 722 = r1, so I have to solve for r2 then use that, subtract r1 and use the acceleration and the displacement to find the time elapsed. After looking online and seeing how others attacked this problem, I'm just confused. Could someone explain the actual concept to me?