Thread: Sailing
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Old 03-18-2008, 10:23 AM   #100
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Originally Posted by tk102
Correct observation but wrong conclusion. You are assuming that the volume of ice remains constant when it melts but it does not.

1. The volume of water displaced by ice is the volume of the ice that is submerged in the water.

2. Gravity acts on the ice and the displaced water identically. Llike a balance scale, the force of the ice pushing down into the water is balanced by the force of the water pushing up due to water being displaced. Because gravitational acceleration is constant, equal forces mean equal mass. Therefore the mass of the ice is equal to the mass of the water displaced.

3. Ice has a specific gravity of about 0.92. That means that 100cc of ice weighs the same as 92cc of water (92g) and thus 100cc of ice will displace 92cc of water and the other 8cc will be floating above the surface.

4. When the ice melts into water its mass stays the same as before (92g) but now it only takes up 92cc. The volume of the melted ice is the same as the volume of water displaced by the solid ice.

Conclusion: No change in displacement of water due to melting ice.
Fair enough, I was still partially right, but not knowing enough about physics, not right enough.

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