Difficulty: Easy
Correct Answer: Disagree
Explanation:
Introduction:
This question distinguishes between strain energy, proof resilience, and modulus of resilience — closely related but different terms in materials engineering.
Given Data / Assumptions:
Concept / Approach:
Strain energy is the work done by internal forces stored as recoverable energy during deformation. Proof resilience is the maximum strain energy a body can store up to the elastic limit. Modulus of resilience is this maximum per unit volume.
Step-by-Step Solution:
1) Let U be strain energy at any load within the elastic range.2) Increase load up to the elastic limit; the maximum stored energy is U_max.3) Definition: proof resilience = U_max (value at elastic limit).4) Therefore, calling “the total strain energy stored in a body” proof resilience is inaccurate unless it is specifically the maximum at the elastic limit.
Verification / Alternative check:
If stress–strain is linear: U_max = 0.5 * sigma_y * epsilon_y * Volume; modulus of resilience = 0.5 * sigma_y * epsilon_y.
Why Other Options Are Wrong:
Agree: ignores the crucial qualifier “up to elastic limit”.
Agree only for elastic bodies: still misses the “maximum at elastic limit” definition.
Agree if volume is unit: that corresponds to modulus of resilience, not proof resilience.
Common Pitfalls:
Confusing proof resilience (total at elastic limit) with modulus of resilience (per unit volume), and with generic strain energy at arbitrary load levels.
Final Answer:
Disagree
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