Question

Law of flotation states
(A) Weight of a flotation body is equal to weight of the liquid displaced.
(B) The centre of gravity of a floating body and the centre of buoyancy are different lines.
(C) Both
(D) None

Answer 1

Hint: Here we can use Archimedes’ principle which states about how much force excreted by an object on fluid and how much force excreted by the fluid on an object. Also says how much fluid displaced by the body. Archimedes’ principle is all about the relation between densities of the body and the object.

Complete step-by-step answer:
The origin of the law of flotation is Archimedes’ principle states that when an object is dipped or partially dipped in fluid, the fluid exerts force on that object on its touching surface towards perpendicular to its touching surface. The fluid exerts buoyancy force equal to the weight of the displaced fluid.

As shown in figure \[m\] is the mass of an object which exerts force of the gravity on the fluid and according to Newton’s \[{{3}^{rd}}\] law of motion the fluid also exerts force perpendicular to the touching surface buoyancy force \[{{f}_{b}}\].
Therefore on the basis of relative densities the body floats on the fluid and displaces fluid according on its mass.

So, the correct answer is “Option A”.

Additional Information:
When a solid body dipped into a fluid the fluid exerts buoyancy force on body and body exerts gravitational force on the fluid. If the force of buoyancy and gravity is the same then the body remains in equilibrium. Archimedes’ principle depends only on specific gravity which we can say density of object by density of fluid which says that if density of overall body less than density of fluid then body floats on the fluid with some of its part dipped in fluid. Here also the fluid exerts buoyancy force equal to the weight of the displaced fluid.

Note: Archimedes’ principle is not differing from Newton’s third law. Note that in case the body floats on fluid or sinks in fluid or partially floats on fluid this law is equally applicable. The more fluid is displaced by fully sinks body then the fluid displaced by partially sinks body.