Answer:
[tex]A=1.4598 cm^2[/tex]
Explanation:
The cross sectional area of the hole can be find using
Δ[tex]A=2*\alpha *A_0*T'[/tex]
[tex]A-A_0=2*\alpha*A_0*T'[/tex]
[tex]A=A_0*(2*\alpha*T'+1)[/tex]
[tex]T'=156-24.2=131.8C[/tex]
[tex]A_0=\pi *r^2[/tex]
[tex]A_0=\pi *0.68cm^2=1.452 cm^2[/tex]
Steel coefficient [tex]\alpha=1.2x10^{-5}C^{-1}[/tex]
replacing to find A
[tex]A=1.4552cm^2*(2*1.2x10^{-5}C^{-1}*131.8C+1)[/tex]
[tex]A=1.4598 cm^2[/tex]
