Elastic energy terminology The capacity of a strained body to do work upon removal of the straining force is called:

Introduction / Context:
When loads are applied to an elastic body, work is done and stored as recoverable potential energy. The correct terminology distinguishes total stored energy, energy at the elastic limit, and energy to fracture. Using precise terms avoids ambiguity in design calculations, fatigue assessment, and impact problems.

Given Data / Assumptions:

• Body deformed elastically by external force.
• Upon unloading, energy is released as the body returns toward its original shape.
• Linear elasticity for simplicity.

Concept / Approach:
Strain energy is the total energy stored due to deformation, recoverable on unloading. Resilience is the ability to absorb energy elastically; proof resilience is the strain energy at the elastic (proof) limit. Modulus of toughness pertains to the total area under the stress–strain curve up to fracture (energy per unit volume), and impact energy is typically measured in Charpy/Izod tests up to fracture.

Step-by-Step Solution:
Define strain energy U = ∫ F dx (or = ∫ sigma d epsilon * volume).For linear springs: U = 1/2 * k * x^2; for linear stress–strain: energy density = 1/2 * sigma * epsilon.Upon unloading, recoverable work equals stored strain energy.

Verification / Alternative check:
Energy conservation and unloading path for linear elasticity show the same triangular area under the force–deflection curve being released.

Why Other Options Are Wrong:
Resilience describes capacity in the elastic range but is not the general term for total stored energy. Proof resilience refers specifically to the energy at the elastic limit. Impact energy and toughness involve fracture processes, not purely elastic recovery.

Common Pitfalls:
Interchanging resilience with strain energy; ignoring the distinction between total energy and energy per unit volume (moduli).

Final Answer:
strain energy