1. The problem statement, all variables and given/known data Suppose there is a square plate, of side a and mass M, whose corners are supported by massless springs, with spring constants K, K, K, and k <= K (the faulty one). The springs are confined so that they stretch and compress vertically, with unperturbed length L. The density of the plate is uniform. (it's a car so the square plate is the chassis and the springs are the suspension) Explain why the system requires three generalised coordinates to be described completely. 2. Relevant equations - 3. The attempt at a solution I'm just really having a hard time visualizing the actual motion of the plate on the springs. I know there should be a generalized coordinate associated with the displacement of the spring, for each spring.. but I can't make the connection and reduce the number to 3 generalized coordinates, as specified. I'm thinking that the springs on opposite corners are somehow related..i.e as one goes up the other goes down, but what happens to the 2 other springs in this case? thanks in advance.