Question
Physics Question on Hooke's Law
The adjacent graph shows the extension (Δl) of a wire of length 1 m suspended from the top of a roof at one end with a load W connected to the other end. If the cross-sectional area of the wire is 10−6m2, calculate the Young's modulus of the material of the wire.
A
2×1011Nm−2
B
2×10−11Nm−2
C
3×10−12Nm−2
D
2×10−13Nm−2
Answer
2×1011Nm−2
Explanation
Solution
From the graph l=10−4m,F=20N \hspace35mm A = 10^{-6} m^2 , L = 1 \, m \therefore \hspace30mm Y = \frac{FL}{Al} \hspace40mm = \frac{20 \times 1}{10^{-6} \times 10^{-4}} \hspace40mm = 20 \times 10^{10} = 2 \times 10^{11} \, Nm^{-2}