Beam ABCD is loaded with a point load P at C as shown in Figure Q3(a). The beam has a hollow cross section as shown in Figure Q3(b). Given, E-200 GPa and oy = 250 MPa. The material is elastic perfectly plastic. i. ii. 11. iv. V. A What is the Moment required for the cross-section to start to yield? (2 marks) What is the Moment required for the cross-section to become a plastic hinge (fully plastic)? (2 marks) What is the load P to cause the plastic hinge? (2 marks) Sketch the residual stress distribution due to release of the plastic hinge load. (3 marks) Explain what happens to the value of load P if the cross-section is rotated 90 and why? (1 mark) muu 0.1 m 0.3 m Figure Q3(a)/Rajah S3(a) 0.2m All Thickness 10 mm 100 mm 150 mm. Figure Q3(b) /Rajah S3(b)