Final answer:
Elastic deformation conserves energy within an object as recoverable elastic potential energy, while plastic deformation dissipates energy as heat or through internal structural changes, making it non-recoverable.
Step-by-step explanation:
The difference in energy conservation during elastic and plastic deformation relates to how energy is stored and dissipated within a material. During elastic deformation, when a force causes a temporary change in the shape or size of an object, such as stretching a spring or plucking a guitar string, the work done is stored as elastic potential energy in the object. The energy can be fully recovered if the deformation does not exceed the material's elastic limit, as described by Hooke's law, which states that potential energy (PEel) is equal to the spring constant (k) multiplied by the displacement squared (x2), or PEel = kx2.
In contrast, during plastic deformation, material undergoes permanent change, failing to return to its original shape after the stress is removed. The energy used to cause plastic deformation is not fully recoverable; it is dissipated as heat or work on microstructural changes within the material. In summary, energy conservation is associated with reversible elastic deformations, whereas energy is lost or dissipated during irreversible plastic deformations due to material yielding or changes in internal structure.