Final answer:
The question pertains to Physics and focuses on the mechanical concepts of force, energy, and stresses, typically taught at the high school level.
Step-by-step explanation:
The question provided seems to relate to the concept of force and energy in the context of Physics, aligning with the principles of mechanics and the study of how forces affect the motion of objects. Specifically, it deals with compression and springs, which are common topics in a high school physics curriculum.
For instance, the scenario about compressing a spring by x and then 2x relates to Hooke's Law and work done in compressing a spring. The work required to compress a spring is proportional to the square of the displacement, according to the formula W = 1/2 kx^2, where W is work, k is the spring constant, and x is the displacement of the spring from its equilibrium position.
As for the question about compressive stress in a pillar, it ties into static mechanics and material science. Compressive stress is calculated by dividing the force by the area over which the force is applied (σ = F/A). Compressive strain is a measure of deformation and is the ratio of the change in length to the original length (ɛ = ΔL/L0).