Physics
posted by Eric .
A brass lid screws tightly onto a glass jar at 20 oC. To help open the jar, it can be
placed into a bath of hot water. After this treatment, the temperature of the lid and the
jar are both 60 oC. The inside diameter of the lid is 8.0 cm at 20 oC. Find the size of the
gap (difference in radius) that develops by this procedure.

the coefficent of area expansion is twice that of the coeff of linear expansiosn.
http://www.engineeringtoolbox.com/linearexpansioncoefficientsd_95.html
From the increase in area, calculate the change in diameter.