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Each steel rail is 10 m long in winter. The linear expansion coefficient of steel is 0.000012 per degree C, and the temperature rises by 15 degree C in summer. Find the gap that should be left between consecutive rails.

1. 0.0018 m
2. 0.0012 m
3. 0.0022 m
4. 0.05 m

Correct answer: 0.0018 m

Solution

The required gap equals the thermal expansion of the rail: delta L = L * alpha * delta T = 10 * 0.000012 * 15 = 0.0018 m.

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