# Action and reaction pair for buoyant force.

• kennykwong
In summary, according to Newton's Third Law, every action has an equal and opposite reaction. This applies to buoyant force as well, where the force of water on an object is met with an equal and opposite force from the object on the water. However, there is no specific name for this reaction force. The buoyant force for a floating body is a reaction to the weight of the body, which is equal to the weight of the fluid displaced by the body according to Archimedes' Principle. These forces are not a force pair, but rather act on the object. The buoyant force is not specifically in reaction to the weight of the body, but rather the integral of pressure over the surface of the body. This remains true
kennykwong
According to Newton 3rd law, every action will have a reaction. but how about buoyant force? if the buoyant force is the force of water on object then the reaction force will be the force of object on water. but is it other name for this force?

Yes, there is an equal and opposite force from the object on the water. I'm not aware of any specific name for it.
Bear in mind that the buoyant force is the integral of the pressure over the surface (as a vector), and the reaction force is likewise.

The buoyant force for a floating body is produced in reaction to the weight of the body.
By Archimedes Principle, the weight of a floating body is equal to the weight of fluid displaced by the body.

SteamKing said:
The buoyant force for a floating body is produced in reaction to the weight of the body.
By Archimedes Principle, the weight of a floating body is equal to the weight of fluid displaced by the body.

this is what i thought at first but when comes to action and reaction force pair, should it be somethings like force of water on object and object on water. furthermore, the weight is the force which act from gravity to the object not from water right? i think weight and buoyant force are the forces acting ON the OBJECT but not a force pair.
please correct me if i am wrong

SteamKing said:
The buoyant force for a floating body is produced in reaction to the weight of the body.
By Archimedes Principle, the weight of a floating body is equal to the weight of fluid displaced by the body.
For a floating body at equilibrium (not being accelerated) the two forces will be equal, but I wouldn't say the buoyant force is in reaction to the weight of the body. It is just the integral of the pressure over the surface of the body, and this is true whether the body is sinking, bobbing up and down, resting on the ocean floor... The equal reaction from the body is in the same manner, distributed over its surface.

## 1. What is an action and reaction pair for buoyant force?

An action and reaction pair for buoyant force refers to the equal and opposite forces that act on an object immersed in a fluid. The buoyant force, which is an upward force exerted by the fluid on the object, is equal in magnitude but opposite in direction to the weight of the fluid displaced by the object.

## 2. How does the buoyant force affect the motion of an object?

The buoyant force acts in the opposite direction to the weight of the object, creating an upward force that counteracts the force of gravity. This results in a net force acting on the object, causing it to either float or sink in the fluid.

## 3. What factors determine the magnitude of the buoyant force?

The magnitude of the buoyant force is determined by the density of the fluid and the volume of the object submerged in the fluid. The more dense the fluid and the larger the volume of the object, the greater the buoyant force will be.

## 4. Can the buoyant force act on objects in any fluid?

Yes, the buoyant force can act on objects in any fluid, whether it is a liquid or a gas. This is because all fluids exert pressure on objects immersed in them, resulting in a buoyant force being exerted on the object.

## 5. How is buoyant force important in everyday life?

Buoyant force plays a crucial role in our everyday lives, particularly in activities like swimming and boating. It also allows ships and other heavy objects to float on water, making transportation of goods and people possible. In addition, the concept of buoyancy is also important in understanding weather patterns and the behavior of hot air balloons.

• Introductory Physics Homework Help
Replies
11
Views
599
• Introductory Physics Homework Help
Replies
62
Views
3K
• Introductory Physics Homework Help
Replies
7
Views
516
• Introductory Physics Homework Help
Replies
2
Views
1K
• Introductory Physics Homework Help
Replies
7
Views
880
• Introductory Physics Homework Help
Replies
11
Views
3K
• Introductory Physics Homework Help
Replies
16
Views
1K
• Introductory Physics Homework Help
Replies
17
Views
1K
• Introductory Physics Homework Help
Replies
6
Views
885
• Classical Physics
Replies
11
Views
1K