When the system is at zero degrees $(0\backslash$deg C$),$ a gap of $1\mathrm{.}2$mm is

present between the two cylinders. Cylinder A is made of concrete while cylinder

B is made of copper. The temperature is then raised to $125\backslash$deg C$.$ Determine:

$($a$)$ The normal stress in the two cylinders;

$($b$)$ The position of the contact point of the two cylinders relative to point A