A brass disc is stuck in a hole of a steel plate. Should you heat the system to free the disc from the hole? Given, alpha for brass =19 times 10^(-6@)C^(-1)" and " alpha for steel =12 times 10^(-6@)C^(-1).

A brass disc is stuck in a hole of a steel plate. Should you heat the

1.	A brass disc is stuck in a hole of a steel plate. Should you heat the system to free the disc from the hole? Given, alpha for brass =19 times 10^(-6@)C^(-1)" and " alpha for steel =12 times 10^(-6@)C^(-1).
Answer» Solution :To free the disc from the hole, the system should cooled. Since `alpha_(brass) GT alpha_(steel)`, and INITIALLY the radii of the disc and the hole were the same, the disc EXPANDS more on HEATING and GETS stuck more tightly. On cooling, the disc contracts more than the hole, and thus becomes free.