Question

explain why it is easier to lift a stone under water than in air

Answer 1

It is easier to lift a stone under water than in air because under water , water is applying a buyont force which reducing the effect of muscular force applied by us.

Answer 2

The density of water is 1000 times greater than the density of air. Also when we lift a stone in water there we get a supportive force called buoyancy or upthrust force which push the stone in upward direction and it helps in lifting the stone.

The buoyancy force given by the water is directly proportional to the water displaced by the stone and hence we need less force to lift the stone in water as compared to that in the air as there is very minor or say no buoyancy due to less dense air.