The correct option is(C): 10 km
\(X _{ COM }=\frac{ m _{1} x _{1}+ m _{2} x _{2}}{ m _{1}+ m _{2}}\)
\(R =\frac{\frac{ M }{4} x +\frac{3 M }{4} \times \frac{ R }{2}}{ M }\)
Horizontal range is given as
\(r_{\frac{M}{4}}=\frac{r}{2}+d=2+8=10km\)
\(=10 Km\)

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. 
Let \( \alpha = \dfrac{-1 + i\sqrt{3}}{2} \) and \( \beta = \dfrac{-1 - i\sqrt{3}}{2} \), where \( i = \sqrt{-1} \). If
\[ (7 - 7\alpha + 9\beta)^{20} + (9 + 7\alpha - 7\beta)^{20} + (-7 + 9\alpha + 7\beta)^{20} + (14 + 7\alpha + 7\beta)^{20} = m^{10}, \] then the value of \( m \) is ___________.
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