Two discs of moment of inertia $I_1$ and $I_2$ and angular speeds ${\omega _1}\,{\rm{and }}{\omega _2}$ are rotating along collinear axes passing through their centre of mass and perpendicular to their plane. If the two are made to rotate together along the same axis the rotational $KE$ of system will be 

  • A

    $\frac{{{I_1}{\omega _1} + {I_2}{\omega _2}}}{{2({I_1} + {I_2})}}$

  • B

    $\frac{{({I_1} + {I_2})\,{{({\omega _1} + {\omega _2})}^2}}}{2}$

  • C

    $\frac{{{{({I_1}{\omega _1} + {I_2}{\omega _2})}^2}}}{{2({I_1} + {I_2})}}$

  • D

      None of these

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