Answer the following questions: a. Write five properties of element stiffness matrix b. Write five properties of structural stiffness matrix c. Write five properties of the global stiffness matrix d. Will subdividing a truss element into many smaller elements improve the accuracy of the solution? Explain e. Explain when element force P is positive or negative. f. For a given spring element, explain why we cannot calculate nodal displacement u and u when nodal forces f and are given. g. Explain what "striking-the-rows" and "striging-the-columns" mean. h. Explain why we need to define the local coordinates x-y in 2D truss element. i. Explain how to determine the angle of a 2D truss element. j. When the connectivity of an element is changed from i →j to j → 1, will the global stiffness matrix be the same or different? Explain why