Consider the system shown in figure below. Assume the mass of cantilever beam is m = 5000kg, the tip mass m = 100 kg, the flexural rigidity of two beans (Young's modulus multiply by moment of inertia) is EL = 18 MNm? and I = 19 m The two beams are connected by a spring with stiffness k = 90 kN/m Ignore the mass of the simply supported beam (shown as massless in the figure) Determine the natural frequency of the system in Hz 2 2 El El massless 777 1.59 Hz 0.57 Hz 0.51 Hz O 103 H: 1.88 Hz