Mechanics.......!!!

$By\quad Energy\quad conservation\quad we\quad can\quad write\quad Mgh=\frac { 1 }{ 2 } M{ V }^{ 2 }\left[ 1+\frac { { K }^{ 2 } }{ { R }^{ 2 } } \right] \\ so\quad the\quad conclusion\quad is\quad more\quad the\quad ratio\quad of\quad \frac { { K }^{ 2 } }{ { R }^{ 2 } } \quad more\quad is\quad the\quad height\quad reached.\\ So,\quad remembering\quad the\quad ratios\quad of\quad disc\quad and\quad all\quad stuff\\ \\ Ring\quad is\quad the\quad answer...$