=+Problem 2.12 A N-storey building is modelled as a series of masses interconnected by springs as displayed on Figure 2.18.e. All masses and springs are equal except for the foundation which has a mass equal to M. The system undergoes seismic motion described as imposed horizontal acceleration ü. The degrees-of-freedom are noted as (q0, q1, … qN), q0 being the displacement of the foundation. You are asked: