Final answer:
The correct answer is a) Normal, shear. Normal stress relates to axial forces causing tension or compression, while shear stress involves forces causing layers within a material to slide against each other.
Step-by-step explanation:
The change in any dimension associated with normal- or shear-induced displacements is known as deformation. The correct answer is a) Normal, shear. When we talk about normal stress, we are typically referring to forces that cause changes in length, such as tension or compression. An axial force results in this type of normal stress, leading to either stretching (tension) or compressing (compression) of a material along its length. On the other hand, shear stress is associated with sideways forces that cause layers within a substance to slide against each other. This type of deformation does not change the transverse length but results in a displacement along the plane of the forces.
For example, when two antiparallel forces of equal magnitude are applied tangentially to opposite surfaces, as illustrated in Figure 12.24 and Figure 5.16, it results in shear deformation. The shear deformation is quantified by the shift Ax of layers in the direction tangent to the forces and is expressed as a ratio of this displacement to the transverse distance Lo.