A copper wire of length 3 m is stretched by 3 mm by applying an external force. The volume of the wire is 600 10-6 m3. The elastic potential energy stored in the wire in stretched condition would be J. (Given Young modulus of copper = 1.1 1011 N/m2)
33
Strain = ll= 3 10-33=10-3
Energy density u= 12 = 12Y(strain)2
U= 12Y(strain)2 V
= 12 1.1 1011 (10-3)2 600 10-6
=0.55 105 600 10-6
U=33 J
Answer: 33
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