The bar has a cross-sectional area A , length L ,
modulus of elasticity E , and coefficient of thermal
expansion a. The temperature of the bar changes uniformly
along its length from T A at A to T B at B so that at any point
x along the bar T = T A + x(T B - T A )>L. Determine the
force the bar exerts on the rigid walls. Initially no axial force
is in the bar and the bar has a temperature of TA.