Upthrust: Weight of Object or Fluid?

[coconut62]

I got confused with the Archimedes theory.

I want to ask if upthrust equals to the weight of the fluid displaced by the object, or is it the weight of the object itself?

I thought it should be weight of fluid since fluid has it's own density which determines it's mass which in turns affect the weight acting upwards...But i did came across some people who say that it has to be the actual weight of the object in order to achieve equilibrium.

 

[voko]

If the upthrust always equals the weight, can anybody ever NOT be in equilibrium? And what happens in reality?

 

[coconut62]

LOL thanks!