Answer: <u>elastically</u> deformed or <u>non-permanently</u> deformed
Explanation:
According to classical mechanics, there are two types of deformations:
-Plastic deformation (also called irreversible or permanent deformation), in which the material does not return to its original form after removing the applied force, therefore it is said that the material was permanently deformed.
This is because the material undergoes irreversible thermodynamic changes while it is subjected to the applied forces.
-Elastic deformation (also called reversible or non-permanent deformation), in which the material returns to its original shape after removing the applied force that caused the deformation.
In this case t<u>he material also undergoes thermodynamic changes, but these are reversible, causing an increase in its internal energy by transforming it into elastic potential energy.</u>
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Therefore, the situation described in the question is related to elastic deformation.