We can't use the nitrogen present in the atmosphere although 80% of the atmosphere consists of nitrogen only.We get this from the plants called as leguminous plants which can convert or fix atmospheric nitrogen into usable ones..
Kindly checkout the attached pic. It contains all your required questions.
One of the greatest examples of entropy working in everyday life is the fact that a messy room is the norm. So if you clean your room it will likely become messy over a period of time, and work will have to be put in to make it orderly again.
According to the formula you have given us to work with . . .
1). The airplane's acceleration is
(80 m/s north - zero) / (20 sec) = 4 m/sec^2 north
2). For the cyclist:
(V-final - zero) / 20sec = 0.5 m/s^2 south
Multiply each side by 20s : V-final = 0.5 m/s^2 south x (20sec) =
10 m/s south
