A train of weight \(10^7\ N\) is running on a level track with uniform speed of \({36\, km\, h^{-1}}\). The frictional force is 0.5 kg f per quintal. If \(g ={ 10 \, m \, s^{-2}}\), power of engine is

Potential energy (V) versus distance (x) is given by the graph. Rank various regions as per the magnitudes of the force (F) acting on a particle from high to low. 
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