QUESTION [30 Marks] Figure below shows a scenario within the oil and gas industry involving a hollow drill pipe used for oil well operations. This drill pipe has specific dimensions, including an outer diameter of 80 mm, a wall thickness of 5 mm, and a weight of 0.7 kN/m. It is subjected to both torque and axial loads, as depicted in the figure below. (a) Calculate the total stresses at a specific point on the pipe's surface at section 'a,' resulting from both axial load and torque. (b) [5 Marks] By construct Mohr's circle, determine the following stress state at a point on its surface at section a. Determine: (i) The principal stresses; (ii) The maximum-in-plane shearing stress; (iii) The orientation of the principal plane. 1.8 kN.m 8 kN 5 m 5 m [15 Marks] (c) Discuss the practical applications of Mohr's Circle within the realm of mechanics and materials, emphasizing its significance in mechanical and civil engineering within the oil and gas industry. Provide references to support your explanation. -END OF QUESTION PAPER- [10 Marks]