Engineering Hydrostatic Pressure of Ball Floating in Liquid

AI Thread Summary
The discussion centers on understanding the hydrostatic pressure of a floating ball in a liquid, focusing on the relationship between the densities of the ball and the liquid. The pressure at a depth 𝑑 is influenced by both the ball's density 𝑝𝑏 and the liquid's density 𝑝𝐿, with the condition for floating being 𝑝𝑏 < 𝑝𝐿. Participants clarify that pressure at the bottom of the ball is uniform along a horizontal line at depth 𝑑. The confusion arises regarding how the liquid's density factors into the hydrostatic pressure equation, with questions about whether to consider the ratio or difference of the densities. Ultimately, the discussion emphasizes the importance of both densities in determining the pressure experienced by the floating object.
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Homework Statement
An object floats in liquid. The depth of the object below the surface is d and its height above the water is h. The density of the ball is p_b and the density of the liquid is p_liq. What is the pressure at the bottom of the object? The pressure above the water is P_atm.
Relevant Equations
hydrostatic equation: dP/dz = -pg
Let's say there's an object floating in liquid. The depth of the object below the surface is 𝑑 and its height above the water is β„Ž. The density of the ball is 𝑝𝑏 and the density of the liquid is 𝑝𝐿. The pressure above the water is π‘ƒπ‘Žπ‘‘π‘š.

I understand this situation when only the density of the ball matters; you integrate to get P(z) = 𝑝𝑏𝑔𝑧 + C, and given the initial condition P(d) = π‘ƒπ‘Žπ‘‘π‘š. (pressure at water-air interface is atmospheric), C = π‘ƒπ‘Žπ‘‘π‘š - 𝑝𝑏𝑔𝑑 , so P(z) = 𝑝𝑏𝑔𝑧 + π‘ƒπ‘Žπ‘‘π‘š - 𝑝𝑏𝑔𝑑

What I am confused about is how to find the pressure given the influence of the density of the liquid. I don't really understand why or how the density of the liquid affects the equation for pressure at all, besides that in order for the object to be floating, 𝑝𝑏< 𝑝𝐿. It seems like since you're only interested in the ball, so the only distance that matters is the distance of the ball under the water, and the only density relevant there would be the one of the ball. Or do you take the ratio of the densities? Is it their difference? Why does the liquid matter at all?
 
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Welcome!
I believe that the pressure at the bottom of the floating ball is the same for all the points located along a horizontal line at a d distance under the surface of the liquid.
 
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Lnewqban said:
Welcome!
I believe that the pressure at the bottom of the floating ball is the same for all the points located along a horizontal line at a d distance under the surface of the liquid.
Hey, thanks! That part makes sense! But how does the density of the liquid relate to the density of the liquid in the hydrostatic equation?
 
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