A piece of ice, with a stone frozen inside it, is floating in water contained in a beaker. When the ice melts, the level of water in the beaker
rises
falls
remains unchanged
falls at first and then rises to the same height as before.
Let the mass of ice be and the mass of stone be
. The mass of the displaced water is equal to
If
is the density of water, the volume of water displaced is
When the ice melts, additional volume of water obtained is . The stone sinks in water, and displaces a volume of water equal to its own volume, which is
where
is the density of stone. Thus the total volume of extra water is
Since
. Therefore, level of water in beaker decreases.