Buoyant Force in High vs Low Density Liquids: Homework Statement & Solution

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When an object is submerged in a higher density liquid, it floats higher compared to a lower density liquid, which raises questions about its stability. The buoyant force acting on the object is equal in both liquids when floating, but the stability depends on how much of the object is submerged. A greater submerged volume generally indicates higher stability, as it reduces the likelihood of the object tipping over when disturbed. The discussion emphasizes the importance of understanding the relationship between buoyant force, density, and stability, while also highlighting the need for careful reasoning about these concepts. Ultimately, the stability of an object floating in a denser liquid is influenced by its submerged volume and the forces acting on it.
  • #31
haruspex said:
Yes, that would generally be true.
So, the reason that the object is less stable in more dense water is because when the object float higher in liquid, it has more tendency to turn over?
 
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  • #32
chetzread said:
So, the reason that the object is less stable in more dense water is because when the object float higher in liquid, it has more tendency to turn over?
Yes. But as I posted, that is only the general trend. There may be exceptions according to shape.
 
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  • #33
haruspex said:
Yes. But as I posted, that is only the general trend. There may be exceptions according to shape.
Exception according to shape? Can you explain further?
 
  • #34
The trick is to realize what gives rise to the stability.
To do that, draw the same shape in two different liquids, as per my example to start with, then do another sketch with them a bit tilted over.
Look to see where the forces act (hint: pressure is perpendicular to the surface, and the pressure at the sides is also important.)

Do you understand where the buoyancy force comes from in the first place?

(I know I said "tomorrow but I have insomnia - and I saw post #25 before post #24 for some reason.)
 
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  • #35
Simon Bridge said:
The trick is to realize what gives rise to the stability.
To do that, draw the same shape in two different liquids, as per my example to start with, then do another sketch with them a bit tilted over.

Look to see where the forces act (hint: pressure is perpendicular to the surface, and the pressure at the sides is also important.)

Do you understand where the buoyancy force comes from in the first place?

(I know I said "tomorrow but I have insomnia - and I saw post #25 before post #24 for some reason.)
Here it is, so what are you trying to say?
 

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  • #36
is there anything to do with the metacentric height , buoyant point in this question ?
 
  • #37
chetzread said:
is there anything to do with the metacentric height , buoyant point in this question ?
Not specifically. I just wanted to alert you to the fact that the topic is subtler than may appear, that it might not actually be true that the object would always be more stable in the lighter fluid, and that even if it is a rigorous proof would not be easy.
 

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