In figure $1,$ a planar truss system is given. According to the given:

a$)$ Find out the global rigidity matrix of the truss member.

b$)$ Find out the force vector.

c$)$ Find out the displacements.

d$)$ Find the element's stresses.

e$)$ Find the reactional forces.

f$)$ Comment that, why do we use truss elements? What are the advantages of truss elements? Can you give a real life examples?

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