# Calculate the increase in energy of a metal wire of length 20cm and area of cross section 1cm square when compressed by a force of 5kg weight along its length.(y=100000000000)?

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by sami123

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by sami123

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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.