Determine whether the object is floating or not

  • Thread starter thumn
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In summary: Integrating gives the following: the total weight of the object is W = ρR2h. The object will float if the normal force on the base of the container is less than the weight of the object, so the normal force is F = W/ρ. So the object will float in equilibrium if the displacement of the object from equilibrium is less than F(x), where x is the position of the object in the liquid.
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thumn
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I have this homework question in fluids.
A cylindrical object has one of its flat ends painted red and the other painted green. It has a radius R and height H and has a nonuniform density given by the function ρ = 6αH + 4αh where h is the distance measured from the red end, and α is a positive number with units of density per length.
(a) Will this object float in a container of liquid of density ρliq = 9αH or will it sink? (Make an argument using math.)
(b) If it floats, what orientation will it float in stable equilibrium, and how much of the cylinder will be submerged? If it sinks what is the normal force that the base of the container exerts on the cylinder? (Either way, draw a diagram.)

Here is my answer so far: i know that to determine if the object is float or sink, we compare the density of the object and density of the liquid.
My concern is that: how can I proceed when the density of object is not constant (nonuniform)?
 
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  • #2
thumn said:
I have this homework question in fluids.
A cylindrical object has one of its flat ends painted red and the other painted green. It has a radius R and height H and has a nonuniform density given by the function ρ = 6αH + 4αh where h is the distance measured from the red end, and α is a positive number with units of density per length.
(a) Will this object float in a container of liquid of density ρliq = 9αH or will it sink? (Make an argument using math.)
(b) If it floats, what orientation will it float in stable equilibrium, and how much of the cylinder will be submerged? If it sinks what is the normal force that the base of the container exerts on the cylinder? (Either way, draw a diagram.)

Here is my answer so far: i know that to determine if the object is float or sink, we compare the density of the object and density of the liquid.
My concern is that: how can I proceed when the density of object is not constant (nonuniform)?
Use integration to figure out the total weight, and the volume is fixed by the rigid container's dimensions.
 
  • #3
thumn said:
I have this homework question in fluids.
A cylindrical object has one of its flat ends painted red and the other painted green. It has a radius R and height H and has a nonuniform density given by the function ρ = 6αH + 4αh where h is the distance measured from the red end, and α is a positive number with units of density per length.
(a) Will this object float in a container of liquid of density ρliq = 9αH or will it sink? (Make an argument using math.)
(b) If it floats, what orientation will it float in stable equilibrium, and how much of the cylinder will be submerged? If it sinks what is the normal force that the base of the container exerts on the cylinder? (Either way, draw a diagram.)

Here is my answer so far: i know that to determine if the object is float or sink, we compare the density of the object and density of the liquid.
My concern is that: how can I proceed when the density of object is not constant (nonuniform)?
Sooner or later, you'll need to find the mass of the object. This will make it easier to determine if it is floating than by comparing the density of the object (which is non-uniform) with the density of the fluid.
 
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Related to Determine whether the object is floating or not

1. What is the definition of an object floating?

An object is considered to be floating if it is suspended or resting on the surface of a liquid, with the majority of its weight being supported by the buoyant force of the liquid.

2. How do you determine if an object is floating or sinking?

You can determine if an object is floating or sinking by comparing its density to the density of the liquid it is placed in. If the object has a lower density than the liquid, it will float. If the object has a higher density, it will sink.

3. Can an object float in any type of liquid?

No, an object can only float in a liquid if its density is lower than the density of the liquid. For example, a wooden block will float in water, but will sink in oil because oil is more dense than water.

4. Does the size or shape of an object affect its ability to float?

Yes, the size and shape of an object can affect its ability to float. Objects with a larger surface area will experience more buoyant force and are more likely to float than smaller objects. The shape of an object can also impact its density, which determines whether it will float or sink.

5. What is the significance of determining if an object is floating or not?

Determining if an object is floating or not can help scientists understand the properties of different materials and liquids. It also has practical applications, such as understanding the buoyancy of ships and designing floating structures.

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