Stress And Strain: Stress: All material bodies are composed of molecules and these molecules are held together by the molecular forces of attraction. Normally, the molecules occupy specific positions. When an external force acts upon a body, the distance between the molecules changes. On stretching a body, its molecules are pulled apart. On compressing a body, its molecules are brought closer. In any case, the relative displacement of various parts takes place. The displaced particles tend to return to their positions. Thus, a restoring force is called into play within the body which tends to bring the body back to … Continue reading Stress And Strain