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Question
Explain why an iron needle sinks in water, but a ship made of iron floats on water.
Solution
Density of iron is more than density of water,
∴ weight of iron nail is more than the weight of water displaced by it and nail sinks. While the shape of the iron ship is made in such a way that it displaces more weight of water than its own weight. Secondly, the ship is HOLLOW and THE EMPTY SPACE contains air which makes the average density of ship less than that of water and hence ship floats on water.
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