Thread: Buoyancy

Two same cones are immersed in the water.
The buoyancy is equal to the difference of pressure suffered by the upper and nether surface of the object immersed in the water.
The buoyancy ia also equal to the weight of the fluid displaced by the object.
I have a queston now:
If a cone inverted immersed and a cone are normally immersed in the water,the difference of pressure are no same,so the buoyancy of them are also no same.
But they displaced the same weight of water,so their buoyancy are same.

How to explain this?

Can somebody answer me?

What is the difference in pressure and why is it "no same"? How does a difference in pressure lead to a buoyant force?

The difference in pressure(water) means the difference pressure(water) suffered by upper and bottom surface of an object immersed in the water.It equal to buoyancy.
The buoyancy is caused by the difference pressure suffered by upper and botoom surface of an object immersed in the water.but,my question........

By bouyancy, you are referring to force, whereas pressure is force per unit area. The pressure changes because there is a larger surface area, but the total force does not, as the mass of the cone and the total volume submerged do not change.

From how you've phrased it, I think this is the answer you were looking for...

Originally Posted by ~James~

Two same cones are immersed in the water.
The buoyancy is equal to the difference of pressure suffered by the upper and nether surface of the object immersed in the water.

No. In fact the dimensions of this statement are inconsistent.

Originally Posted by ~James~

The buoyancy ia also equal to the weight of the fluid displaced by the object.

Correct

Originally Posted by ~James~

I have a queston now:
If a cone inverted immersed and a cone are normally immersed in the water,the difference of pressure are no same,so the buoyancy of them are also no same.
But they displaced the same weight of water,so their buoyancy are same.

How to explain this?

Only your second statement of Archimedes principle is correct.