Question

Hey!

Can somebody explain me about the Buoyancy & the Buoyant Force?

Class 9th, Physics. ​

Answer 1

In simple words

Buoyant force is the magnitude of force which is exerted by fluid,when any object is immersed in it and this characteristic or property of fluid is referred as buoyancy.

Magnitude of buoyant force:-

Actually magnitude of buoyant force is equal to the weight of the liquid it displaces which is also refered as Archimedes principle.

Factor affecting the buoyancy:-

i)density of fluid

ii)density of object

why buoyant force is dependent on fluid density?

As said above , buoyant force is equal to the magnitude of weight of liquid displaced by object.

and we know that weight depends on mass and that mass depends on density.

so,more will be the density ,more will be the mass and then more will be the weight of liquid displaced which is equal to buoyant force.

density of object:-If the density of object will be more then it will have more weight so it can displaced large amount of water,to.increase the buoyant force.

Some more facts related to density of objects

Case1):-density of water>density of object

In this case, object will float

Case2):-density of water,<density of object

object will sink

Case3):-density of object=density of water

partial floatation of object

Answer 2

$\large{\underline{\underline{\sf{Buoyant\:Force-}}}}$

It is an upward perpendicular force exerted by liquid on the surface of objects, when they are immersed in a liquid.

In other words, It is perpendicular upward force acting to the lower surface of any object when it is dipped fully or partially in any liquid. It is true that every liquid exerts an upward thrust (buoyant force) on the objects immersed in them. So, it is the tendency of every liquid that no object and can dip in them completely.

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$\bold{\underline{Magnitude\:of\:Buoyant\:Force-}}$

Magnitude of buoyant force depends upon the density of objects. Mathematically, buoyant force is directly proportional to the density. Hence more will be the density, greater would be the buoyant force and vice versa. Nature of buoyant force is also dependent upon the quality of water. More the salty water, greater will be the buoyant force and vice versa. This is the reason, sea water has more buoyant force the river or pond's water.

$\large{\underline{\underline{\sf{Buoyancy-}}}}$

It is the phenomenon of exertion of upward thrust that is buoyant force on the objects when they are immersed in the liquids.