Answer
Iron
Work Step by Step
We know that
$k=\frac{4L\Delta Q}{\pi D^2\Delta t\Delta T}$
We plug in the known values to obtain:
$k=\frac{4(0.2)(4.5\times 10^4)}{\pi(0.02)^2(3600)(100)}$
This simplifies to:
$k=79.6$
We know that iron has a thermal conductivity $80\frac{W}{mK}$. Thus, the road is made of iron.
