A2. Two identical simple pendulums are connected via a spring as shown in Figure A2. The length of the pendulum strut L = 0.5m and the mass of the attached bob m = 2kg. The stiffness coefficient of the connecting spring is k = 80 Ns/m.
a) Using the free-body diagram method, derive the following governing equations for the coupled pendulum system, which are given below in matrix form:
b) Using the characteristic equation method or transformation to principal coordinates, find out two frequencies and modes of oscillation for the system.
c) Describe the method of exciting separately each mode of vibration separately in the coupled pendulums shown in Figure A2.