A body is under stress F and has Young’s modulus Y, then the energy stored per unit volume equals to

Options

(a) F²/2Y
(b) Y/2F²
(c) 2Y/F²
(d) 2F²/Y

Correct Answer:

F²/2Y

Explanation:

Energy stored per unit volume,
u = (1/2) x stress x strain
= (1/2) x stress x [stress/Young’s modulus]
( ·.· Young’s modulus = stress/strain)
= (1/2) x F x (F/Y) = F²/2Y.