Answer:
160 m
Explanation:
The intensity, I, of the sound is inversely proportional to the square of the distance, r, from the source.

Hence,


From the question,
is half of 



Answer:Transformer
Explanation:All the other devices generate their own electricity apart from power line and Transformer, power line just carries electricity. A transformer can be used to step up or step down voltages from a source.
Answer:
it would be 39.2 m/s
Explanation:
After one second, you're falling 9.8 m/s. After two seconds, you're falling 19.6 m/s, and so on.