1. The problem statement, all variables and given/known data 2 equal masses 'm' are attached to a spring of spring constant 'K' and unstretched length 'L'. The system is rotating about its centre of with an angular velocity 'w'. The linear velocity 'v' of m is comparable to that of speed of light 'c'. Find a relation between the Angular Momentum 'J' and the total energy 'E'. 2. Relevant equations Hooke's law. Centripetal force. relativistic mass equation. 3. The attempt at a solution I started off by equating the Force in the spring K (2r - L), where 2r is the compressed length of the spring; with the Centripetal force γm.w^2.r I obtained the expression for r using this. Using r, i obtained the Angular momentum using J = (2γm).w.r^2 Now I cannot figure out how to obtain a relation between J and the total energy E. Help? Thanks in advance.