A rocket, starting from rest, travels straight up with an acceleration of 59.2 m/s2. When the rocket is at a height of 615 m, it produces 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 1 3 I. Assuming that the speed of sound is 343 m/s, find the time that has elapsed between the two measurements.