Question

The brass bar and the aluminum bar in the drawing are each attached to an immovable wall. At 26.6 °C the air gap between the rods is 1.78 x 10-3 m. At what temperature will the gap be closed? the brass is 2.0 m and aluminum is 1.0 m. they are facing each other. I cannot put the pic up. It wont let me.

please show work and formula step by step

Answer 1

ΔL total = ΔL forbrass + ΔL for aluminum

                 = L α ΔT for brass + L αΔT for alum

   0.00178 =  2.0 * 19 x 10^-6 * ΔT   +   1.0 * 23 x 10^-6 * ΔT

  1780 = 38 ΔT   + 23 ΔT

ΔT = 29.18032 deg C

so the final temp is 29.18032 + 26.6 = 55.78032787 C =============ANSWER)