1. The problem statement, all variables and given/known data: Find the equation of motion for the system below (see the attached files) https://www.physicsforums.com/attachment.php?attachmentid=58905&stc=1&d=1369155073 Solve the problem with the state vector approach. Choose realistic values on k1,k2,c1,M and F 2. Relevant equations See the attatched file. https://www.physicsforums.com/attachment.php?attachmentid=58906&stc=1&d=1369155073 3. The attempt at a solution I am having trouble finding the right equation of motion for this system since it has two degrees of freedom and only one mass. For a "normal", where there is a mass at every node, I have not had a problem so far. I would appreciate any help or tips how to handle this problem! Thank you very much!