Extracted text: Determine the natural frequency of a weight w simply supported beam (Fig. PI.12). The length of the beam is L, and its flexural rigidity is EI. The spring stiffness is k. Assume the beam to be massless. 1. suspended from a spring at the midpoint of a * based on the strength of material course, please find the formula of stiffness for simply supported beams. w= 25 kN 50 cm E = 23000 MPa 30 cm L= 3.00 m k=45 kN/m EI k Figure P1.12