Basic material property — recovery after unloading The property that enables a body to return to its original shape and size upon removal of the deforming force is called:

Introduction / Context:
Material property definitions are the foundation for interpreting test data and selecting materials. This question contrasts elasticity with other properties commonly discussed in mechanics of materials.

Given Data / Assumptions:

• Small deformation, uniaxial loading for clarity.
• Deforming force is removed completely.

Concept / Approach:
Elasticity: ability to recover original shape and size when unloaded.Plasticity: tendency to retain permanent deformation after unloading.Ductility: ability to undergo significant plastic strain in tension before fracture.Malleability: ability to undergo plastic deformation in compression (e.g., rolling, hammering into sheets).Toughness: ability to absorb energy before fracture (area under stress–strain curve).

Step-by-Step Solution:

Verification / Alternative check:
Examine a typical stress–strain curve: unloading from within the elastic region retraces the loading path and returns to zero strain.

Why Other Options Are Wrong:

• Plasticity involves permanent set, not full recovery.
• Ductility and malleability describe modes of plastic deformation, not recovery.
• Toughness is an energy-absorption measure and unrelated to shape recovery upon unloading.

Common Pitfalls:
Using ductility or malleability as catch-all terms for “good” mechanical behavior; they are specific to plastic deformation, not elasticity.

Final Answer:
Elasticity