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Homework Help: Mass-spring-mass system rotating about its centre of mass relativistically

  1. Jun 29, 2012 #1
    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.
  2. jcsd
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