Question

The ____________ forces are used are used in the method of sections for the calculation of the internal forces.

(a) Internal rotational

(b) Couple rotational

(c) Translational

(d) External

This question was addressed to me in an interview.

This question is from Internal Forces Developed in Structural Members topic in division Internal Forces of Engineering Mechanics

Answer 1

The correct choice is (d) External

To explain: The calculations of the method of sections involve the making of the free diagrams and then use external forces to determine the internal forces. Design so as to withstand the loads which are going to be added to the beams. Thus the loads which are being added externally are being used in the free body diagrams.