A massless string is wrapped round a disc of mass $M$ and radius $R$. Another end is tied to a mass $m$ which is initially at height $h$ from ground level as shown in the fig. If the mass is released then its velocity while touching the ground level will be

830-655

  • A

    $\sqrt {2gh} $

  • B

    $\sqrt {2gh} \,\frac{M}{m}$

  • C

    $\sqrt {2ghm/M} \,$

  • D

    $\sqrt {4mgh/2m + M} \,$

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