How is a wire's Young’s modulus defined in terms of stress and proportional length change________________?
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Answer: B. same amount
Explanation
Hooke law establishes that tensile stress is directly proportional to longitudinal strain within the elastic limit. Young modulus is defined as the constant ratio of this linear stress to strain relationship. Consequently, doubling the stress results in a proportional doubling of strain, keeping the ratio the same. Young modulus is a mechanical property measuring the stiffness of a solid elastic material. The proportional limit marks the upper stress threshold where Hooke law remains valid for metals. Standard units for Young modulus are pascals or gigapascals in the SI system.
Civil engineers use Young modulus values to calculate elastic deflections in beams and columns. Selecting materials with high stiffness prevents excessive sagging in precision machine tools. Tensile test data plotted on stress-strain diagrams yield the numerical value of Young modulus. Option A incorrectly implies the modulus value changes by half when stress is altered. Option C suggests the modulus doubles, violating the constant ratio principle of elastic materials. Options D and E introduce arbitrary scaling factors that contradict the linear elasticity equations.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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