Question

The direction cosine n is given by formula _____

(a) \(\frac{x_2-x_1}{l_e}\)

(b) \(\frac{y_2-y_1}{l_e}\)

(c) \(\frac{z_2-z_1}{l_e}\)

(d) Undefined

I had been asked this question in an international level competition.

My question is taken from Three Dimensional Trusses in division Trusses of Finite Element Method

Answer 1

The correct answer is (c) \(\frac{z_2-z_1}{l_e}\)

The explanation: A truss is a two node element. The three D truss element can be treated as straight forward generalization of the 2D truss element.