E_rotational = 1 over 2 I %omega^2 newline E_rotational = 1 over 2 I {v^2} over {r^2} newline F_centripetal = {m v^2} over r newline v = sqrt{{r F_centripetal} over m} newline E_linear = 1 over 2 m v^2 newline E_linear = 1 over 2 r F_{centripetal} newline