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A heavy chain is fixed at both ends. When you pull the middle of the chain downward so that it forms a triangular shape, does the centre of mass of the chain move upward, downward, or stay at the same position compared to its original hanging configuration?
- Centre of mass moves downward
- Centre of mass moves upward
- Centre of mass remains stationary
- Cannot be predicted
Correct answer: Centre of mass moves upward
Solution
In the natural catenary, most of the chain hangs near the bottom. When pulled into a triangle, the two inclined straight segments carry the chain to higher positions on average. Therefore the centre of mass rises.
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