Final answer:
The problem deals with determining the resisting moments at the fixed ends of a two-part composite bar under torsion, identifying the maximum stress in each part and calculating the angle of twist for each section.
Step-by-step explanation:
The question is regarding the application of torques and stresses on a composite circular bar, where a twisting moment is applied at a certain point along the bar's length, and the individual moments and stresses at various points, as well as the angle of twist, must be determined. This falls under the subject of physics, particularly the area of mechanics and materials science. This would be evaluated at the college level due to the complexity of the engineering concepts involved.
To find the values of the resisting moments at the ends A and C, one would have to consider the principle of moments and equilibrium, where the sum of torques must equal zero. Applying torsion equations will yield the values for resisting moments. Maximum stress can be calculated using the formula for torsional stress, which is τ = T*r/J, where τ is the stress, T is the torque, r is the radius, and J is the polar moment of inertia. The angle of twist for each section is derived from the formula θ = TL/(GJ), where θ is the angle of twist, T is the torque, L is the length of the section, and G is the modulus of rigidity of the material. Since the diameters and lengths of the bar segments differ, the maximum stress and angle of twist will vary for sections AB and BC.