Engineering
Physics
Stress Strain and Hookes Law New
Question

Statement-1: Elastic forces can be conservative even beyond proportionality limit
Statement-2: Materials can be streched even beyond proportionality limit. (point till which Hooke's law is valid is called proportionality limit)

Statement-1 is true, statement-2 is false.

Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement-1.

Statement-1 is false, statement-2 is true.

Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1.

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Solution

Elastic forces are conservative only when the work done by them is path-independent and depends solely on initial and final positions. Within the proportionality limit (where Hooke's law, F=kx, holds), elastic forces are conservative. However, beyond this limit, materials undergo plastic deformation, and the force-displacement relationship becomes irreversible and path-dependent, making the force non-conservative. Thus, Statement-1 is false.

Statement-2 is true: materials can indeed be stretched beyond the proportionality limit, entering the plastic region.

Final Answer: Statement-1 is false, statement-2 is true.