What Weight Can a Wooden Block Support Before Sinking?

In summary: The buoyant force on the block is the weight of the displaced fluid. So in order for it to float, you would need to add 105 kg of weight to it. That's it!
  • #1
astru025
163
0

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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  • #2
It sure would be nice if this problem had some units attached to it.
 
  • #3
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.
 
  • #4
Units: mass: kg, weight: N, volume: m^3, density: kg/m^3, buoyant force: N.
 
  • #5
Thank you :)
What about the principle of Archemedes?
 
  • #6
I don't know that... It is no where in my notes
 
  • #7
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?
 
  • #8
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?
 
  • #9
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...
 

1. What is the purpose of a Physics buoyant force lab?

The purpose of a Physics buoyant force lab is to experimentally demonstrate the principles of buoyancy, which is an upward force exerted by a fluid on an object immersed in it. This lab helps in understanding the relationship between the buoyant force and the density of the fluid and the object.

2. How is buoyant force calculated in this lab?

In this lab, buoyant force is calculated by measuring the weight of an object when it is fully immersed in a fluid and comparing it to the weight of the object when it is partially immersed in the fluid. The difference in weight is equal to the buoyant force acting on the object.

3. What materials are needed for a Physics buoyant force lab?

The materials needed for a Physics buoyant force lab may include a graduated cylinder, a scale, objects of different densities, and a container filled with water or any other fluid.

4. How does the density of an object affect the buoyant force in this lab?

In this lab, the density of an object directly affects the buoyant force acting on it. Objects with higher density will experience a greater buoyant force compared to objects with lower density. This is because the buoyant force is equal to the weight of the fluid displaced by the object, and objects with higher density displace more fluid.

5. What are some real-life applications of buoyant force demonstrated in this lab?

Buoyant force has several real-life applications, such as in shipbuilding, where the design of a ship's hull takes into account the buoyant force to ensure it can float. It is also used in the design of life jackets and other flotation devices. Additionally, understanding buoyant force is crucial in the study of ocean and atmospheric phenomena, such as ocean currents and weather patterns.

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