++++ ++++ ++++ ++++ ++++ Concept Question ++++ ++++ ++++ ++++ ++++ By looking at the potential energy of an element, what can you conclude about the properties required for the basis functions of an Euler-Bernoulli beam element? 1. They should be di?erentiable twice. 2. The required polynomial order of interpolation is 4, so that we can accomodate non-zero shearing forces at the nodes. 3. The slopes at the end nodes of the element should be part of the nodal unknowns and the basis func- tions should be such that continuity of the slope is guaranteed at the element boundaries. 1. ++++ Statement (1) and (3) 2. ++++ All of the above statements 3. ++++ Statement (2) 4. ++++ None of the above statements 5. ++++ DKDU The correct answer is ++++