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

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Homework Help Overview

The discussion revolves around applying Archimedes' principle to analyze the forces acting on a submerged cube in a liquid. The problem involves calculating various forces, including the downward force from the liquid and atmosphere, the upward buoyant force, and the tension in the rope suspending the cube.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the relationships between the forces acting on the cube, including the downward force on the top and the upward force on the bottom. There is uncertainty about the calculation of the upward force and its relation to buoyancy. Some participants question the definitions of variables used in the equations.

Discussion Status

Some participants have provided calculations for the forces, while others are seeking clarification on specific terms and relationships among the forces. There is an ongoing exploration of how to approach the calculations for parts B and C, with hints being offered to guide understanding.

Contextual Notes

Participants are working under the constraints of a homework assignment, which may limit the information they can access or the methods they can use. There is also a mention of needing hints rather than complete solutions, reflecting the forum's learning-first approach.

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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