Mechanical Properties Of Solids Ques 3

3. When an elastic material with Young’s modulus $Y$ is subjected to stretching stress $S$, elastic energy stored per unit volume of the material is

[1989]

(a) $YS / 2$

(b) $S^{2} Y / 2$

(c) $S^{2} / 2 Y$

(d) $S / 2 Y$

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Answer:

Correct Answer: 3.(c)

Solution:

  1. (c) Energy stored per unit volume

$=\frac{1}{2} \times$ stress $\times$ strain

$=\frac{1}{2} \times$ stress $\times($ stress $/$ Young’s modulus $)$

$=\frac{1}{2} \times(\text{ stress })^{2} /($ Young’s modulus $)=\frac{S^{2}}{2 Y}$