= At a temperature of 9°C, a 3-mm gap exists between two polymer bars and a rigid support, as shown in the figure. Bars (1) and (2) have coefficients of thermal expansion of a₁ = 139 x 10-6/°C and a2 70 x 10-6/°C, respectively. The supports at A and C are rigid. Determine the lowest temperature at which the 3-mm gap is closed. Assume L₁= 480 mm and L₂ = 580 mm.

= At a temperature of 9°C, a 3-mm gap exists between two polymer bars and a rigid support, as shown in the figure. Bars (1) and (2) have coefficients of thermal expansion of a₁ = 139 x 10-6/°C and a2 70 x 10-6/°C, respectively. The supports at A and C are rigid. Determine the lowest temperature at which the 3-mm gap is closed. Assume L₁= 480 mm and L₂ = 580 mm.