The wooden wheel of radius R is made of two semicircular parts (see figure). The two parts are held together by a ring made of metal strip of cross-sectional area S and length L. L is slightly less than 2πR. To fit the ring on the wheel, it is heated so that its temperature rises by ΔT and just steps over the wheel. As it cools down to the surrounding temperature, it presses the semicircular parts together. If the coefficient of linear expansion of the metal is α, and its Young's modulus is Y, the force that one part of the wheel applies on the other part is:
2πSYαΔT
SYαΔT
πSYαΔT
2SYαΔT
Solution:
ΔL = LαΔT Tension in the ring is T. TA = ΔL/L Y T = αΔTYS So, F = 2T F = 2αΔTYS