Final answer:
Bending a long bone puts it in compression on one side and tension on the other, similar to other weight-bearing structures. The arrangement of trabeculae in bones helps accommodate these opposing forces. Bone fractures usually result from twisting or bending rather than pure tension or compression.
Step-by-step explanation:
When a long bone is subjected to bending, it experiences compression on one side and tension on the other side. This is similar to how a long shelf loaded with books will sag and experience compressive stress on the top surface and tensile stress on the bottom surface.
The structure of bones is such that they can handle these loads, but most bone fractures occur from excessive twisting or bending, not just from tension or compression.
The ability of bones to withstand these stresses is partly due to the arrangement of trabeculae in spongy bone, where one side bears tension and the other side withstands compression. In engineering terms, materials like bone can exhibit different values in Young's modulus for tensile and compressive stresses, indicating the measure of the stiffness of the bone when under tension or compression.
Shear modulus, another mechanical property, is notable in bones, as it is greater than its Young's modulus, allowing bones to be long and thin yet strong.