Answer :
The energy is strain energy and given by (0.5*stress*strain)
E = 0.5*stress*strain
= 0.5*stress*(stress/y)
=(stress)²/2y
stress = force/area
force = 5kg weight = 5*9.8N = 49 N
area = 1 cm² = 10^-4 m²
stress = 49/10^-4 = 4.9*10^5 N/m² = 4.9*10^5 Pa
y = 10^11 Pa
E = (4.9*10^5)²/2*10^11 J
= 2.4*10^11 / 2*10^11 J
= 1.2 J
Energy stored is 1.2 J.
E = 0.5*stress*strain
= 0.5*stress*(stress/y)
=(stress)²/2y
stress = force/area
force = 5kg weight = 5*9.8N = 49 N
area = 1 cm² = 10^-4 m²
stress = 49/10^-4 = 4.9*10^5 N/m² = 4.9*10^5 Pa
y = 10^11 Pa
E = (4.9*10^5)²/2*10^11 J
= 2.4*10^11 / 2*10^11 J
= 1.2 J
Energy stored is 1.2 J.