1. The problem statement, all variables and given/known data 2. Relevant equations PE spring = .5 kx^2 KE rotation = .5 I w^2 3. The attempt at a solution I tried to do a conservation of energy (Note: I = moment of inertia, L = length) 3*.5*k L^2 = .5 I w^2 I =3 M R^2 ---> a^2 = b^2 + c^2 -2bc cos(a) (the reason why I am using law of cosines is to find the radius from the center to each point mass) R = L / sqrt(3) I = ML^2 3*.5*k*L^2 = .5*M*L^2 *w^2 k = 1/3 * Mw^2 which is wrong. The answer is C. How do you do this?