Answer:
Explanation:
We can see from the question that

and 
% of 
=> 
from the question
% of 
Substituting this into the equation

=> 



From the equation above


D= 9.7^3/(69)(4.2)^2
d=912.673/289.8^2
d=912.673/83984.04
d=0.01086721953362...
I hope this helped!
Answer
The challenge when trying to protect the environment is expensive clean energy startup cost
Explanation
In attempts to protect the environment, energy users across the globe are shifting to new renewable energy resources which are faced by the challenge of high capital cost. Renewable energy technologies are cheap to operate but very expensive to build. The perception is that renewable energy resources are risky because they require higher construction costs.
Seems to me that it flies 400 m/s there and 600 m/s back the same distance.
therefore the average of 400 and 600 is 500 m/s. The distance is the same so the normal formula of (d2-d1)/(t2-t1) is applicable.