ANS:B - completely reversed

A material being tested for endurance strength is typically subjected to the completely reversed load. Endurance strength testing, also known as fatigue testing, involves subjecting the material to repeated cycles of stress or strain. In completely reversed loading, the stress or strain alternates between tension and compression with equal magnitudes but opposite directions. This type of loading mimics the conditions that materials experience in real-world applications where they undergo cyclic loading, such as in rotating machinery, vehicles, and structural components subjected to fluctuating loads. By subjecting the material to completely reversed loading, engineers can evaluate its resistance to fatigue failure and determine its endurance strength, which is the maximum stress or strain amplitude that the material can withstand for a specified number of cycles before failing. This testing helps ensure the reliability and safety of materials and components under cyclic loading conditions.