Question P.233: A steel bar 50 mm in diameter and 2 m long is surrounded by ...

\begin{aligned}& \delta=\frac{P L}{A E}\\& \delta=\delta_{c a s t\ i r o n}=\delta_{s t e e l}=0.8\mathrm{~mm}\\& \delta_{c a s t\ i r o n}=\frac{P_{c a s t\ i r o n}(2000)}{\left[\frac{1}{4}\pi(60^{2}-50^{2})\right](100000)}=0.8\\& P_{c a s t\;i r o n}=11000\pi\:\mathrm{N}\\& \delta_{s t ee l}=\frac{P_{steel}(2000)}{[\frac{1}{4}\pi(50^2)](200\ 000)}=0.8\\& P_{s t e e l}=50\,000\pi\,\mathrm{N}\\\\& \textstyle{\Sigma}F_{V}=0\\& P=P_{c a s t\;i r o n}+P_{s t e e l}\\& P\,=\,11\, 000\pi+50\,000\pi\\& P=61\,000\pi\,\mathrm{N}\\& P=191.64\,\mathrm{kN}\end{aligned}