Question

in a vessel a large block of wood is floating while an iron nail submerged​

Answer 1

An iron nail sinks in water but can float on

Answer 2

In a vessel, a large block of wood is floating while an iron nail submerged is because of the difference in density.

Density is the mass of an object divided by its volume. Density often has units of grams per cubic centimetre (g/cm3).

1. Our surroundings naturally are set up in a manner where heavy/ dense density objects submerge whereas the light density objects stay above the denser objects.
2. The density of water (assumed as water as the question is asked regarding floating) here should be taken between the densities of an iron nail and a block of wood, in the middle.
3. When the densities are added to the equation, it gets clearer. The iron nail with the heaviest density among the three objects (iron nail, block of wood and water) is submerged.
4. Water that has a density lesser than the iron nail but more than the block of wood is between the two objects, in the centre. Thus, the lightest density object- block of wood is on the top that we perceive as floating.