Important conceptual questions of fluid statics class 12

1. A dead body floats in water but a living body sinks in water. Why?
   Ans: The dead body has greater volume than the body of living. So, the dead body becomes lighter than water and hence floats in it.
2. Why is the bottom of a ship made heavy? Explain.
   Ans:When the bottom of a ship is heavy, the centre of gravity (C.G.) of the ship lies below the centre of buoyancy (C.B.) and hence, meta-centre (C.M.) of the displaced liquid and the floating ship comes stable condition even it's equilibrium position is distributed. So, this makes the stability of the ship.
3. Why does ice floats on water?
   Ans: Density of ice is less than density of water. Therefore, ice floats in water.
4. Why is it easier to lift a body in a liquid than in air?
   Ans: The density of a liquid is greater than that of air. Since, the upthrust depends on the density, the upthrust acting on the body is greater in water than in air and it is easier to lift the body in water.
5. Distinguish between density and specific gravity.
   Ans: Density of a body is the ratio of mass of a body to its volume, while the specific gravity is simply the ratio of weight of water to the weight of equal volume of water. So, density of the body has a unit kg/m³ while the specific gravity has no unit.
6. The bags and suitcase are provided with broad handles. Why?
   Ans: The broad handles on bags and suitcases distribute the weight of the object over a larger area, reducing the pressure on the hand and making it more comfortable to carry.
7. Does a ship sink more in river or in sea water? Explain.
   Ans: A ship sinks more in sea water than in river water due to the higher density of sea water. The upthrust force on the ship is the same in both river and sea water because it depends on the volume of water displaced by the ship, which is the same for the same weight of the ship in both river and sea water.