Problem # $4$ Material Changes due to temperature

Figure $1$: Plan View

Figure $2$: Section ViewOn a chilly morning, $($see temperature below$)$ a piece of railroad track steel is cut to match $($length given below$)$ the end of a $2$ ft tall concrete wall that it is laying on top of $($see diagram above$).$ The railroad track and concrete wall are fixed at one end and can only expand or contract at the other end of the wall $($the free end$).$

a$)$ Assuming the temperature rises $($see temperature below$),$ what will be the difference in length between the end of the beam and the concrete wall at the free end? $($Answer Format: raw # three decimal places, unit is inches$)$

b$)$ Which will be longer, the concrete or the railroad track? $($Multiple Choice$)$

Given pieces of information:

Length of Railroad track $($at low temperature$)=100\mathrm{.}0ft.$

Coefficient of expansion for steel is in $\frac{?}{?}$ in per $($:$F$