It is pretty clear from archimedes that how an object behaves in terms of floating and sinking when submerged in a liquid is cleary a matter of density of both the object and the liquid. SO consider an infinitely big aquarium , in front of which a man is standing ; the man somehow throws balls into the middle of the aquarium with a finite horizontal velocity. These balls have a density that is equal to that of the liquid in the aquarium . These balls will stop after some time , but after the balls have stopped will they continue to rise vertically in the aquarium ?
some time later ……………
the same man throws balls vertically into a river . this time also the balls have same velocity as that of water. When the balls stop will rise up or remain at that position where they have stopped ?
the Archimedes principle tells me that they will not rise but remain at that spot. I just need a reassurance !
Also i need to clarify one more fact ; if thrown vertically in a big body of water, is it possible for a object with a greater density than that of water to stop midway in the river due to greater density at that point or does this type of object have a enough water level above it which will cancel out the effects of the greater density below ?
Best Answer
If I understood your question correctly, then assuming still water, its density minutely increases with the depth. The object floating at any level, has same density as that of water at that level. This is ignoring internal currents etc. of the water.
In rare cases, the object at a depth may get compressed due to water pressure at that depth and attain a density that is greater than that of water at that level and may sink further. Depends upon what gets compressed more due to water pressure - water itself, or, the object. But eventually it will float at a level where its density matches with that of water, assuming it does not cross the level where its compression rate exceeds that of water.