Upthrust in a fully submerged object

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    Submerged Upthrust
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Discussion Overview

The discussion revolves around the concept of upthrust, or buoyant force, experienced by a fully submerged object, specifically an iron cube placed in water. Participants explore the implications of the cube reaching the bottom of the beaker and the forces acting on it in that scenario.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant states that when the iron cube is submerged, it experiences upthrust, but questions whether it continues to do so when it touches the bottom of the beaker.
  • Another participant explains that the buoyant force is equal to the weight of the water displaced, and after sinking, the beaker exerts an additional force to maintain equilibrium due to the weight of the cube exceeding the buoyant force.
  • A participant asserts that since there is no water below the cube, pressure is exerted on all sides except the bottom, questioning the validity of this assertion.
  • Another participant elaborates that if the cube is stationary, the bottom of the cube will experience a force equal to the weight of the cube plus the weight of the water above it, and discusses the distribution of force if water is present beneath the cube.

Areas of Agreement / Disagreement

Participants express differing views on the nature of forces acting on the cube when it is at the bottom of the beaker, indicating that multiple competing views remain and the discussion is unresolved.

Contextual Notes

There are assumptions regarding the presence or absence of water beneath the cube and the implications of pressure distribution that have not been fully clarified.

Himal kharel
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When we put any object in a fluid it experiences upthrust. Suppose an iron cube is put in a beaker with water. It sinks and reaches bottom. When it reaches bottom and touches the base of beaker there is no water below it. Then will it experience upthrust?
 
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The block experiences a buoyant force equal to the weight of the volume of water displaced...After it sinks to the bottom,because the weight imparted by gravity exceeds the buoyant force, the beaker then exerts an additional force sufficient to keep the block in equilibrium...
 
There is no water below cube. So pressure is exerted on all sides except bottom.
Is my assertion right?
 
If the cube is stationary, its bottom will experience a force equal to the weight of the cube plus the weight of the water in the column above the cube. (Plus the weight of the air in that column extended to the edge of the atmosphere, if we want to be persnickity.) If there is truly no water beneath the cube, that force will be exerted by the bottom of the beaker. If there is some water beneath the cube, the force will be distributed between the beaker and the water.
 

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