Kinetic, thermal, and the temperature of the substance all decrease when the particles slow down.
Answer:
4939200 m
Explanation:
v = Velocity of sound in air = 343 m/s (general value)
For the echo to reach Rip van Winkle it must cover the distance to the mountain twice. So, time taken for the sound traveling to the mountain once

Distance is given by

The distance to the mountain is 4939200 m
The answer is radiator >.<