When a building is constructed at \[-10{}^\circ C\], a steel beam (cross-sectional area \[45\text{ }c{{m}^{2}}\]) is put in place with its ends cemented in pillars. If the sealed ends cannot move, what will be the compressional force in the beam when the temperature is \[25{}^\circ C\]? For this kind of steel, \[\alpha =1.1\times {{10}^{-5}}\,{{\,}^{o}}{{C}^{-1}}\] and \[Y=2.0\times {{10}^{11}}N/{{m}^{2}}\].

When a building is constructed at \[-10{}^\circ C\], a steel beam (cro

1.	When a building is constructed at \[-10{}^\circ C\], a steel beam (cross-sectional area \[45\text{ }c{{m}^{2}}\]) is put in place with its ends cemented in pillars. If the sealed ends cannot move, what will be the compressional force in the beam when the temperature is \[25{}^\circ C\]? For this kind of steel, \[\alpha =1.1\times {{10}^{-5}}\,{{\,}^{o}}{{C}^{-1}}\] and \[Y=2.0\times {{10}^{11}}N/{{m}^{2}}\].
A.	\[2.5\times {{10}^{3}}N\]
B.	\[3.5\times {{10}^{5}}N\]
C.	\[2.5\times {{10}^{5}}N\]
D.	\[3.5\times {{10}^{3}}N\]
Answer» C. \[2.5\times {{10}^{5}}N\]