Answer:

Explanation:
Assuming uniform spread of sound with no significant reflections or absorption. We know that sound intensity varies
where r is the distance
Since intensity is given then when at 3 m


Since we have the constant then at 4m
Intensity, 
Answer:
If it was only 10 degrees the seasonal changes would lessen and vise versa for 50. meaning the seasonal changes would become more extreme
Explanation:
To charge something or use experiments
Weathering and rock slides
Answer:
Velocity of the passenger = 78.8[km/h]
Explanation:
In order to solve this problem, we must observe the train from a distant point of the train. In this way we can observe that the train moves at 80[km/h] relative to the ground.
In such a way that the passenger moves in a direction contrary to the movement of the train.
![v_{pass}=80-1.2\\ v_{pass}=78.8[km/h]](https://tex.z-dn.net/?f=v_%7Bpass%7D%3D80-1.2%5C%5C%20v_%7Bpass%7D%3D78.8%5Bkm%2Fh%5D)
The Observer located outside the train will see how the passenger moves away at 78.8 [km / h] and not at 80[km/h] which is the speed of the train.