The bar has a cross$-$sectional area $A=0\mathrm{.}0824m^2,$ length $L=18m,$ modulus of elasticity $E=103$GPa,

and coefficient of thermal expansion $a=0\mathrm{.}000046\%.$

The temperature of the bar changes uniformly along its length from $T_A=26C$ at $A$ to $T_B=177C$ at $B$

so that at any point $x$ along the bar $T=T_A+x\frac{T_B-T_A}{L}.$

Determine the force $($in Mega Newton $-$ MN$)$ the bar exerts on the rigid walls. Initially no axial force is in

the bar and the bar has a temperature of $T_A.$

Note: use two decimal points for the answer.