1. Consider the two-mass system in Figure I, where k1 and k2 are spring constants; x1 and x2 are displacements of m1 and m2, assuming that both springs have their natural lengths when x1 = x2 = 0. The surface is frictionless and f is an external force applied to m1.
(a) Choose x1 as the output of the system. Write down the state space representation using
as the state vector, where
denotes the time derivative of
for i = 1,2.