Finding the Density of a Wooden Cube Submerged in Water

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    Buoyancy
In summary, the conversation is discussing the density of a solid wooden cube that is 30.0cm on each edge. The cube is able to be completely submerged in water when pushed downward with a force of 54.0N. To determine the density of the wood, the buoyant force and weight equations must be set up and solved. The final answer is 800kg/m^3.
  • #1
psycovic23
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"A solid wooden cube, 30.0cm on each edge, can be totally submerged in water if it is pushed downward with a force of 54.0N. What is the density of the wood?"

I know so far that the buoyant force would equal the 54N, but I don't know how to get the mass of the cube to determine the density. Can you help?
 
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  • #2
So the cube completely submerges into water...

Downward Force + Weight = Buoyant Upward Force

Solve as per above...Show your work..
 
  • #3
No, you don't know the bouyancy force is 54 N! How much would a cube of water, 30 cm on a side, weigh? That's the bouyancy force pushing the wood upward. The weight of the cube, plus the 54N pressing it down must equal that. Set up that equation and you can solve for the weight of the cube of wood.
 
  • #4
Buoyant Force= Density of water x Volume of cube x g

Why the full volume of cube?...

Weight of cube = density of cube x Volume of cube x g

Can you solve further?
 
  • #5
Ah...800kg/m^3! Thank you!
 

1. What is buoyancy and how does it work?

Buoyancy is the upward force exerted by a fluid on an object placed in it. It is caused by the difference in pressure between the top and bottom of the object. The more dense an object is compared to the fluid, the greater the buoyant force will be.

2. How do I calculate the buoyant force on an object?

The buoyant force can be calculated using Archimedes' Principle, which states that the buoyant force is equal to the weight of the fluid displaced by the object. This can be expressed as Fb = ρVg, where Fb is the buoyant force, ρ is the density of the fluid, V is the volume of the displaced fluid, and g is the acceleration due to gravity.

3. What factors affect the buoyancy of an object?

The buoyancy of an object is affected by its density, the density of the fluid it is placed in, and the volume of the object. Objects with a lower density than the fluid will experience a greater buoyant force, while objects with a higher density will sink. The shape and size of the object can also affect its buoyancy.

4. How can I increase the buoyancy of an object?

To increase the buoyancy of an object, you can either decrease its density or increase the volume of the object. For example, you can add air to a balloon to increase its volume and decrease its overall density, making it more buoyant.

5. How does buoyancy play a role in objects floating or sinking in water?

If an object's weight is greater than the buoyant force acting on it, it will sink. If the object's weight is less than the buoyant force, it will float. This is why objects with a lower density than water, such as wood or plastic, will float, while objects with a higher density, such as rocks, will sink.

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