a$)$ for a mechanism with plastic hinges at A$,$ C$,$ D and E$,$ draw the virtual deformation shape, clearly show all angles

b$)$ for the mechanism in a$),$ calculate the value of W at collapse

c$)$ calculate the bending moments at B for the above mechanism

d$)$ draw the bending moment diagram for the above mechanism showing all significant values of moments

e$)$ give reasons why the mechanism above is an upper bound solution

f$)$ generate a lower bound solution for W and clearly state your reasons