Answer:
The answer to your question is: vo = 25 m/s
Explanation:
data
a = -7.5 m/s²
d = 42 m
vf = 0 m/s
vo = ?
Formula
vf² = vo² - 2ad
Substitution
0² = vo² - 2(7.5)(42)
We clear vo from the equation
vo² = 2(7.5)(42)
vo² = 630 simplifying
vo = 25 m/s result
The total distance is 4 + 7 = 11 Km
Well plants breathe carbon and let out oxygen so it cleans the air, not sure about the energy use...