What is the correct density of the cork based on its buoyancy and weight?

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    Buoyancy Density
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Homework Help Overview

The discussion revolves around determining the density of a piece of cork based on its weight in air and its buoyancy when submerged in water. The original poster presents their calculations and expresses confusion over their result.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to calculate the density by finding mass and buoyant force, but questions their result. Participants inquire about the definition of buoyant force and suggest reevaluating the calculations.

Discussion Status

Participants are actively engaging with the original poster's calculations, questioning the interpretation of buoyant force and encouraging a review of the force directions. There is no explicit consensus on the calculations yet, but guidance is being offered.

Contextual Notes

There is a mention of a missing figure that is referenced in the problem statement, which may be relevant for understanding the forces involved.

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Homework Statement



A large piece of cork weighs 0.224 N in air. When held submerged underwater by a spring scale as shown in Figure 13-27, the spring scale reads 0.672 N. Find the density of the cork.

Homework Equations



Fb=buoyant force

The Attempt at a Solution


i found mass by doing .224/9.8 so mass=2.286e-2 kg
then i got Fb by doing weight in air minus weight in water so Fb=-.448 N
then i did Fb=(densitywater)(volumeobject)(g) and got the volume of object so volume=4.571e-5 cubic m
last i did density=mass/volume and got the incorrect answer of 5000 kg/cubic meter

If anyone can help me, I don't know where I went wrong. Thanks very much, awe.g
 
Last edited:
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What's an Fb when it's at home? There's no attached figure.
 
what do you mean at home? sorry I am confused
 
idk if that's what you want...justr a picture, doesn't show much though
 

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awertag said:
what do you mean at home? sorry I am confused

Sorry, it's just an expression. Take a look at the directions that the forces act, and re-evaluate your value for Fb.
 
oh ok lol. what does the expression mean exactly? Like originally?

and would Fb be equal to mg?
 
The expression is an inquiry as to what something (or someone) really is.

Fb is the force of buoyancy. It's opposing the weight of the object. Check your calculation for Fb.
 

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