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Roodles01
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Homework Statement
Find magnitude of net upward force on a cube in terms of l, ρ (rho), g and h. then show that h = m/ρl2
A solid cube, mass m, side length l, is placed in a liquid of uniform density, ρ(rho), at a depth h0 below the surface of the liquid, which is open to the air.
The upper and lower faces of the cube are horizontal.
(this is from previous question https://www.physicsforums.com/threads/force-exerted-by-fluid.784711/)
Homework Equations
pressure, p = ρ g h
mass = ρ x volume of liquid displaced
The Attempt at a Solution
Net force, Fn = (pbottom x area of cube face) - (ptop x area of cube face)
p at top face = (pT) x ρliquid x h x g
p at bottom face = (pB) x ρliquid x (h+l) x g
so
Fn = (ρgh + ρlg - ρgh)
Fn = ρlg
Net force - fine.
Er! how do I show that h = m/ρl2
I know m = ρ x v . . .