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प्रश्न
What is the centre of buoyancy? State its position for a floating body with respect to the centre of gravity of the body.
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उत्तर
Centre of buoyancy: It is the point through which the resultant of the buoyancy forces on a submerged body act; it coincides with the centre of gravity of the displaced liquid, if the body is completely immersed.
For a floating body with its part submerged in the liquid, the centre of buoyancy is at the centre of gravity of the submerged part of the body and it lies vertically below the centre of gravity of the entire body.
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संबंधित प्रश्न
A body floats in a liquid when its weight becomes equal to the weight of the liquid displaced by its submerged part.
How does the pressure exerted by thrust depend on the area of surface on which it acts? Explain with a suitable example.
Deduce an expression for the pressure at depth inside a liquid.
The pressure inside a liquid of density p at a depth h is :
(i) The diameter of neck and bottom of a bottle are 2 cm and 10 cm, respectively. The bottle is completely filled with oil. If the cork in the neck is pressed in with a force of 1.2 kgf, what force is exerted on the bottom of the bottle?
(ii) Name the law/principle you have used to find the force in part (a).
A small block of wood is completely immersed in (i) water, (ii) glycerine and then released. In each case, What do you observe? Explain the difference in your observation in the two cases.
You are provided with a hollow iron ball A of volume 15 cm3 and mass 12 g and a solid iron ball B of mass 12 g. Both are placed on the surface of water contained in a large tub.
- Find upthrust on each ball.
- Which ball will sink? Give a reason for your answer (Density of iron = 8.0 g cm-3)
A beaker contains a liquid of density ‘ρ’ up to height ‘h’ such that ‘PA’ is atmospheric pressure and ‘g’ is the acceleration due to gravity. Answer the following questions:
- What is the pressure on the free surface of the liquid?
- What is the pressure on the base of the beaker?
- What is the lateral pressure at the base on the inner walls of the beaker?
Most buoyant objects are those with relatively ______.
- high volume
- higher mass
- low density
- less viscosity
The point at which the force of buoyancy is supposed to act is known as ______.
