(10 marks) A 2m long beam (Fig. 1a ) with a hollow cross-section (Fig. 1b ) is simply supported at both ends. The beam is made of a material with yield strength y=470MPa, tensile strength UTS=570 MPa, Young's modulus E=210GPa and Poisson's ratio v=0.31. The beam is loaded by a distributed load with the intensity that linearly decreases from 2w at the left end to w at the right end. a) Calculate moment Mp of the fully plastic beam crosssection; b) Calculate the w value corresponding to the onset of the plastic collapse