Answer: answer
Explanation:For equilibrium
Weight = Tension
mg=T
∴T=4×3.1π=12.4πN (as can be inferred from the question)
Y=
△l/l
T/A
=
1000
0.031
/20
12.4π/π(
2
)
4×0.031
12.4×20×1000×(1000)
=2×10
12
N/m
