What Weight Can a Wooden Block Support Before Sinking?

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Homework Help Overview

The discussion revolves around a physics problem related to buoyancy, specifically focusing on how much weight a wooden block can support before it sinks. The original poster provides various parameters of the block, including its mass, weight, volume, density, and buoyant force.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the principle of Archimedes and its relation to buoyant force and weight. There are questions about the definitions and implications of buoyancy, as well as the units associated with the measurements provided. Some express uncertainty about how to apply the given equation and seek guidance on the initial steps.

Discussion Status

The conversation includes attempts to clarify concepts and definitions related to buoyancy. Some participants have provided hints and suggestions, while others express confusion about the principles involved. There is no explicit consensus on the approach, but various interpretations and lines of reasoning are being explored.

Contextual Notes

Some participants note the absence of units in the original problem statement and question the completeness of the information provided. There is also a mention of a lack of familiarity with the principle of Archimedes among some participants.

astru025
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Homework Statement


Wooden block: Mass: .095. Weight: .931. Volume: 2.03E-4. Density: 467.98. Buoyant force of block: 1.9894.
- Predict how much weight the wooden block can support before sinking.

Homework Equations



W= m1g + m2g

The Attempt at a Solution


Not sure where to start. If someone could just point me in the right direction that would be great! I have tried many things that haven't worked...

Here is a picture of the whole lab section:
 

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It sure would be nice if this problem had some units attached to it.
 
Hint: start with the principle of Archemedes

Where does the buoyant force come from?
How is it related to the weight?

I'll second the request for units.
 
Units: mass: kg, weight: N, volume: m^3, density: kg/m^3, buoyant force: N.
 
Thank you :)
What about the principle of Archemedes?
 
I don't know that... It is no where in my notes
 
The equation I'm looking to use is W=m1g + m2g and I need to find what m2 is. I'm not sure where to begin plugging in for this equation though. Using the above info maybe someone could help me?
 
I don't know [the principle of Archemedes]... It is no where in my notes
If only you had access to some sort of searchable database where you could just enter search terms and get lists of possible related articles that you could use when your notes fail you? If only someone would make such a thing available for free through any computer?

I find it hard to believe that you have just done a lab on buoyancy without being given a definition of "buoyancy".
What does the term "buoyancy force", used in the lab, mean to you?
 
Archimedes principle: buoyant force= weights of displaced fluid
 
  • #10
Well done:
specifically, an object floats when the buoyancy force is equal to it's weight.

This means: a floating object displaces an amount of fluid equal to it's own mass - but a sunk object, or an object just about to be sunk, displaces fluid equal to it's own volume.

So - what is the buoyancy force on the block when it is as pictured.

Per your question: how much extra mass must you pile on, for the block to float with it's top surface exactly level with the top of the water?
 
  • #11
.105 kg was my final answer which proved tone correct. Thank you very much.
 
  • #12
Well done.

By "correct" do you mean it matched some model answer or that it matched the result of the experiment?
(Or both?)
 
  • #13
Isn't the buoyant force given in the OP?
It says "Buoyant force of block: 1.9894. ".
As well as the block's weight. You just need to subtract the two.
Unless these things are not given.
 
  • #14
nasu said:
Isn't the buoyant force given in the OP?
It says "Buoyant force of block: 1.9894. ".
As well as the block's weight. You just need to subtract the two.
Unless these things are not given.
That's right - all that was needed.
To get there requires realizing what "buoyant force" actually means...
 

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