How Does Archimedes' Principle Apply to Forces on a Submerged Cube?

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SUMMARY

The discussion focuses on applying Archimedes' Principle to analyze forces acting on a submerged cube with an edge length of 0.500 m and mass of 480 kg in a liquid with a density of 1030 kg/m³. The total downward force on the top of the cube, Ftop, is calculated to be 2.59E4 N, while the buoyant force, Fbu, is determined to be 1.26E3 N. The relationship among the forces is established as Fbu = Fbottom + T, indicating the need to calculate Fbottom and tension T in the rope for complete analysis. The participant seeks clarification on how to approach part (b) of the problem.

PREREQUISITES
  • Understanding of Archimedes' Principle and buoyant force calculations
  • Knowledge of pressure calculations in fluids, including gauge pressure
  • Familiarity with Newton's second law and force equilibrium
  • Basic algebra for solving equations involving forces
NEXT STEPS
  • Review the derivation of buoyant force using the formula Fb = pVg
  • Learn how to calculate gauge pressure at different depths in a fluid
  • Study the application of Newton's second law in static equilibrium scenarios
  • Practice solving similar problems involving submerged objects and forces
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Students studying physics, particularly those focusing on fluid mechanics and forces acting on submerged objects, as well as educators looking for problem-solving strategies related to Archimedes' Principle.

brett812718
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Homework Statement


In the figure below, a cube of edge length L = 0.500 m and mass 480 kg is suspended by a rope in an open tank of liquid of density 1030 kg/m3.
(a) Find Ftop, the magnitude of the total downward force on the top of the cube from the liquid and the atmosphere, assuming atmospheric pressure is 1.00 atm.
correct check mark 2.59E4N

(b) Find Fbottom, the magnitude of the total upward force on the bottom of the cube.
wrong check mark N

(c) Find T, the tension in the rope.
N

(d) Calculate Fbu, the magnitude of the buoyant force on the cube using Archimedes' principle.
correct check mark 1.26E3N
What relation exists among all these quantities? (Select all that apply.)
Fbu = Fbottom + T
Fbu = m - T
Fbu = Ftop - Fbottom
Fbu = Fbottom - Ftop
Fbu = T - m

wrong check mark

hint:Force is equal to the product of the (uniform) pressure and the face area. The gauge pressure at a certain depth h in a fluid is equal to ρgh. The gravitational force and the force from the rope also act on the cube. By Newton's second law, the net force must be zero.
Section 14-7 Archimedes' Principle
hrw7_14-37.gif

Homework Equations


Fb=pVg
F=ma

The Attempt at a Solution


I have no idea what to do for part b
at first I thought Fbottom was the same as the buoyancy force but that was wrong.
All I need is a hint on how to start part b and then I should be able to get part c on my own. I have already solved for parts A and D
 
Last edited:
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Think about what caused the force on the top in part A. It is the same type of force on the bottom.
 
A(Po+pg(3/2)L)=2.71E4N
thanks
 
would T=Ftop+mg-Fb-Fbottom ?
 
Can someone help me solve A and B for this problem..?

A(Po+pg(3/2)L)=2.71E4N

what does Po and pg mean in here?
is A = 1.5 in this problem?
 

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