- #1
AudioFlux
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the Archimedes' Principle states that the weight of the fluid displaced is equal to the buoyant force. why/how does that happen?
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How does Archimedes' Principle work?
- Thread starter AudioFlux
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In summary: . so in summary, the buoyant force on a displaced volume of fluid is equal to the weight of the displaced fluid.
- #2
jetwaterluffy
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The fluid is trying to fall below you, and has to push you up and out of the way to do so.
- #3
technician
- 1,506
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Imagine a container of water and picture a volume of the water at some depth in the container. It might help to imagine this volume of water in a plastic bag (ignore the weight of the bag...it is only to help your imagination).
This volume of water will not be sinking or rising so the effect of the rest of the water in the container is to provide a force upwards equal to the weight of the water in the plastic bag.
Now replace the plastic bag of water with an identical volume plastic bag of steel. The water in the container continues to provide an upward force equal to the weight of water that was originally in place. Upward force on steel equals upwards force on weight of water that steel has replaced.
No equations, no complicated maths... hope it helps you cope with any equations and maths that you may meet.
This volume of water will not be sinking or rising so the effect of the rest of the water in the container is to provide a force upwards equal to the weight of the water in the plastic bag.
Now replace the plastic bag of water with an identical volume plastic bag of steel. The water in the container continues to provide an upward force equal to the weight of water that was originally in place. Upward force on steel equals upwards force on weight of water that steel has replaced.
No equations, no complicated maths... hope it helps you cope with any equations and maths that you may meet.
- #4
- #5
AudioFlux
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technician said:
that's cool, but i have already understood how buoyancy is the same for equal displacement of the volume of a fluid. i wanted to know what the displacement of the volume of a fluid has to do with buoyancy and how the mechanism works.
- #6
technician
- 1,506
- 18
The only extra that I can add involves talking about pressure due to a depth of liquid.
If the top of your container is h1 below the surface then the pressure on the top of the container is P = h1ρg and the force on the top of the container is P x A = h1ρgA
Similarly the force on the bottom is h2ρg if the bottom is at a depth of h2.
The upwards force is therefore greater than the downwards for by (h2-h1)ρgA
but this is the weight of the liquid that would occupy the same volume as the oject.
So the upthrust = weight of displaced liquid...(it does not matter whether the displaced liquid came out of the container or not)
I hope this adds to the explanation for you
If the top of your container is h1 below the surface then the pressure on the top of the container is P = h1ρg and the force on the top of the container is P x A = h1ρgA
Similarly the force on the bottom is h2ρg if the bottom is at a depth of h2.
The upwards force is therefore greater than the downwards for by (h2-h1)ρgA
but this is the weight of the liquid that would occupy the same volume as the oject.
So the upthrust = weight of displaced liquid...(it does not matter whether the displaced liquid came out of the container or not)
I hope this adds to the explanation for you
- #7
AudioFlux
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technician said:
thanks you, that answered my question :)
- #8
jetwaterluffy
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AudioFlux said:
In that diagram the ball still has water above it. This water is attracted towards the ground.
- #9
AudioFlux
- 58
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jetwaterluffy said:
oh. right
Related to How does Archimedes' Principle work?
1. How does Archimedes' Principle explain buoyancy?
Archimedes' Principle states that the buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid that the object displaces. This explains buoyancy because when an object is submerged, it displaces a certain amount of fluid which creates an upward force, or buoyant force, that counteracts the force of gravity pulling the object down. The object will float if the buoyant force is greater than the force of gravity, and sink if the buoyant force is less than the force of gravity.
2. What is the relationship between the volume of an object and the buoyant force?
The greater the volume of an object, the greater the buoyant force will be. This is because Archimedes' Principle states that the buoyant force is equal to the weight of the fluid displaced, and the volume of an object determines how much fluid it will displace when submerged.
3. Can Archimedes' Principle be applied to all fluids?
Yes, Archimedes' Principle can be applied to all fluids, whether it is a liquid or a gas. This is because the buoyant force is dependent on the weight of the fluid displaced, not the type of fluid.
4. Does the shape of an object affect the buoyant force?
Yes, the shape of an object can affect the buoyant force. According to Archimedes' Principle, the buoyant force is equal to the weight of the fluid displaced, so the shape of an object can determine how much fluid it will displace. For example, a flat object will displace more fluid than a tall and narrow object, resulting in a greater buoyant force.
5. How does the density of an object affect its buoyancy?
The density of an object plays a crucial role in determining its buoyancy. According to Archimedes' Principle, the buoyant force is equal to the weight of the fluid displaced, so an object with a lower density than the fluid will float, while an object with a higher density will sink. This is why objects made of materials with higher densities, such as metal, will sink in water while objects made of materials with lower densities, such as wood, will float in water.
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