Hi, I didn't understand the exercise so I didn't do it and my teacher doesn't give the details of the solutions. If somewone can help me and explain me the steps.. it'd be great ! Three block of mass m=0.13kg are connected with three springs of constant k1 k2 k3 and Two of the normal modes of the system, expressed in terms of displacement are : |1>=( 1 0 -3) |2>= ( 27 -10 9) Knowing that the lower frequency that isn't necessarly the first mode frequency is 20 rad/s. Find the spring constants. All i did is that i gave the equations of motion so i got few points for that, and found the |3> as they're perpendicular between them. Thank you, I have an exam tomorrow and need to understand this !