Table 1 shows the height of a cavern ceiling, measured using ultrasound pulses, at various horizontal distances from the cave entrance.
| Distance from cave entrance (m) | Height of cavern ceiling (m) |
|---|---|
| 0 | 5.2 |
| 15 | 9.8 |
| 30 | 14.5 |
| 45 | 19.0 |
| 60 | 23.5 |
| 75 | 27.2 |
| 90 | 31.0 |
| 105 | 33.8 |
A speleologist uses an ultrasound rangefinder to measure the height of the cavern ceiling when they are positioned exactly 75 m from the cave entrance.
Calculate the total round-trip travel time of the ultrasound pulse for this measurement.
The speed of the ultrasound pulse in the cave air is 340 m/s.