# Fluid Mechanics of a metal cube

1. Dec 12, 2011

### 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?

2. Dec 12, 2011

### BetoG93

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

3. Dec 12, 2011

### 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?

4. Dec 12, 2011

### BetoG93

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

5. Dec 12, 2011

### Cromptu

Well according to the book, it is..

6. Dec 12, 2011

### BetoG93

What is the title of the book?

7. Dec 12, 2011

### 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.

8. Jan 23, 2012