Final answer:
The two basic forces subjected to individual structural components are compression, where an object is pushed from both ends, and tension, where it is pulled upon. These can cause changes in the object's length, and understanding them is essential in structural engineering. The correct options are both (a) compression and (b) tension.
Step-by-step explanation:
The two basic forces that individual structural components are subjected to are compression and tension. Compression is when an object is pushed from both ends, causing it to be squeezed, while tension is when an object is pulled upon, causing it to stretch. Both of these forces can result in deformation of the material, where deformation includes changes in the original length of the object.
Figure 12.18 illustrates these concepts well, indicating that whether an object is under tension or compression, if the applied force is linear and along the length of the object, the length will change. This change is represented as ΔL, which is the difference between the original length, Lo, and the new length, L.
In structural engineering, understanding these concepts is crucial since structures often experience both tensile and compressive stresses. For example, a beam supporting weight will experience compression on the top side and tension on the bottom side due to bending.
This interplay can be observed in Figure 12.20, where the object bending downward shows both stresses in different sections. As a result, concepts such as Young's modulus of elasticity become very important, as they relate stress and strain and help determine how materials will behave under these forces.
When we talk about structures, stress can also be described as force per unit area, and it can manifest in various forms, including tensile stress, compressive stress, bulk stress, and shear stress, depending on the forces' direction and how they are applied.
The approximate magnitudes of tensile or compressive stress that different materials can withstand before deforming are found in tables such as Table 12.1. In essence, all these concepts play a fundamental role in designing safe and functional structures in engineering.
The correct option that identifies the two basic forces individual structural components are subjected to is d. Both a and b.