A construction worker is goofing around on site and is standing on a wood beam at its center. The worker is shaking up and down as he does his job but eventually the beam fails. The site engineer is called over to analyze the dynamic system to determine why the wood beam has failed. As part of her analysis, she first decides to determine the stiffness of the beam. Determine the equivalent stiffness, k, for the massless beam system shown below (the beam is indeterminate so use compatibility and linearity of the system to solve). Leave your answer in terms of E, I and L. Your degree of freedom is the displacement of the beam in the down direction at the point indicated: -L/2- f -L/2- tu Actual Wood Beam Setup (Worker represents F) k. ΕΙ F Equivalent Spring