Fluid Mechanics of a metal cube

[Cromptu]

A metal cube is placed in an empty vessel. When water is filled in the vessel so that the cube is completely immersed in the water, the force on the bottom of the vessel in contact with the cube :

Ans: Will remain the same.

But how? Won't object exert an extra force which will be (h*density*g) * area of the cube?

 

[BetoG93]

That extra force you mention is in fact the weight of the cube.

 

[Cromptu]

Noo, what I'm saying is that in the second case where the vessel is full of water, won't this force applied by the cube be less because of the buoyant force?

 

[BetoG93]

I think the same. Are you sure this is the correct answer?

 

[Cromptu]

Well according to the book, it is..

 

[BetoG93]

What is the title of the book?

 

[obafgkmrns]

Any buoyancy force acts only on the cube's bottom surface. If there is no water under the cube, there is no buoyancy force, and therefore the force on the bottom of the vessel in contact with the cube remains the same.

 

[mayYang]

this problem is solved in Bar-Meir 's book.
you can get the book at http://www.potto.org/FM/fluidMechanics.pdf
look under the static chapter.
good luck
may,