Final answer:
Using the speed of sound at 16.8°C and the echo return time, the distance to the coastal land is approximately 3.756 km.
Step-by-step explanation:
To calculate the distance to the coastal land, we need to use the speed of sound in air, which depends on the air temperature. The formula for the speed of sound in air at a given temperature in degrees Celsius is v = 331.4 + 0.6T m/s, where T is the air temperature. At 16.8°C, the speed of sound is v = 331.4 + 0.6(16.8) = 341.48 m/s. The total travel time for the sound wave is 22.0 s, which includes the trip to the coastal land and back. Therefore, the one-way travel time is 22.0 s / 2 = 11.0 s.
Using the formula distance = speed × time, the distance to the coastal land is 341.48 m/s × 11.0 s = 3756.28 m or approximately 3.756 km.