Buoyant Force

Buoyant force exerted by different fluids on a given body is :

The _____ density has no units.

Madhu noted following observations in her notebook:
(i) Weight of the stone in the air $=272 \mathrm{gwt}$
(ii) Weight of the stone in water $=192 \mathrm{gwt}$
(iii) Weight of the stone in salt solution $=176 \mathrm{gwt}$
The relative density of the salt solution is

The concept of relative density tells how many times the density of a substance is more (or less) than the density of _____.

What is the unit of Relative Density?

The volume of a $500 \mathrm{g}$ sealed packet is $350 {\mathrm{cm}}^3$. Will the packet float or sink in water if the density of water is $1 \mathrm{g} {\mathrm{cm}}^{-3}$? What will be the mass of the water displaced by this packet?

The volume of $50 \mathrm{g}$ of a substance is $20 {\mathrm{cm}}^3$. If the density of water is $1 \mathrm{g} {\mathrm{cm}}^{-3}$, will the substance float or sink?

Why does a block of plastic released underwater come up to the surface of water?

In what direction does the buoyant force on an object immersed in a liquid act?

You find your mass to be $42 \mathrm{kg}$ on a weighing machine. Is your mass more or less than $42 \mathrm{kg}$?

Why does a body float or sink when placed on the surface of the water?

What do you mean by buoyancy?

Name the force exerted by a fluid in vertically upward direction on a body which is partially immersed in the fluid.

(Choose one of the following: Gravitational force/Buoyant force/Frictional force).

Suppose a cubical block of wood is first immersed in normal water and then in sea water. In which case will you find the wood sinking more?
 

Give the laws of flotation. Explain diagrammatically.