# Magdeburg hemispheres(action and reaction pair)

• asdff529
In summary, the conversation discusses the concept of using two horses to pull Magdeburg hemispheres with the same force as one horse pulling with the hemispheres attached to a tree. The participants also discuss the effect of adding a second spring and meter to the setup, as well as the impact of nailing down the box holding the springs. The conversation also references a historic experiment involving two teams of horses attempting to separate the hemispheres, and the possible use of 16 horses to achieve separation.
asdff529
My friend said that two horses pull the Magdeburg hemispheres with same force is as same as a horse pulls the Magdeburg hemispheres which is tell on a tree(I may forget the details about the assumption)
Why?
Another Q. about action and reaction

i don't know why the reading isn't 2Mg,but is Mg
Assume the strings are light and the pulley is smooth.

I don't understand what the first question is asking, but you can understand the diagram like this. Put a second spring and meter on the other side also, what does it read? (By symmetry, it reads the same as the first side, call this reading W.) Now put a nail through the box on the top, do any of its readings change? (No it still reads W, the reading is how much the string is stretched, it makes no difference if the box the springs are attached to is nailed down or not.) Now remove the second mass altogether, keeping the box nailed down. Does the reading change? (No, it was nailed down, it doesn't matter if the other mass is there or not.) What is that reading, what must W equal?

Analysis is correct.

He is referencing a historic experiment (demonstration) where two teams of horses (8 per side) failed to separate the two halves of an evacuated sphere, the two sides of the sphere having nothing clamping them together but atmospheric pressure.

Someone then suggested that it was unnecessary to use two teams of eight horses, that a single team of eight with the other side chained to a sturdy tree would have tested the same pressure holding the sphere halves together... he was correct, as are you.

Good point, or if one had 16 horses to begin with and wanted to separate the spheres, it would have been better to chain one half to something sturdy, and set all 16 horses to pulling on the other half!

I would like to clarify and explain the concept of action and reaction in relation to the Magdeburg hemispheres. The statement made by your friend is not entirely accurate and may have some incorrect assumptions. The Magdeburg hemispheres are a pair of large copper hemispheres that can be joined together to create a vacuum seal. When the air is pumped out of the hemispheres, they become extremely difficult to pull apart due to the atmospheric pressure pushing them together.

Now, in terms of action and reaction, it is important to understand that the forces acting on the Magdeburg hemispheres are not the same as a horse pulling a tree. In the case of the hemispheres, the force being applied is the atmospheric pressure pushing them together, while in the case of the horse and tree, the force is the horse's muscular strength pulling on the tree's trunk. These are two different types of forces and cannot be compared in the same way.

Furthermore, the assumption of two horses pulling the hemispheres with the same force as one horse pulling them while being tied to a tree is incorrect. In this scenario, the force applied by the horses would be divided between the two hemispheres, making it less than the force applied by one horse pulling on the hemispheres alone. This is due to the principle of action and reaction, where for every action, there is an equal and opposite reaction.

In response to the question about the reading of 2Mg versus Mg, it is important to note that the force of gravity (represented by 'g') is acting on both the hemispheres and the horse. However, in the case of the hemispheres, the force of gravity is acting on both hemispheres, so it is multiplied by 2. Hence, the reading would be 2Mg. In the case of the horse, the force of gravity is acting on the horse alone, so the reading would be Mg.

In conclusion, the concept of action and reaction is important to understand when discussing the forces acting on the Magdeburg hemispheres. It is not accurate to compare the forces in this scenario to a horse pulling a tree, and the assumption of two horses pulling with the same force as one horse while being tied to a tree is incorrect. Additionally, the difference in the readings can be explained by the number of objects on which the force of gravity is acting.

## 1. What are Magdeburg hemispheres?

Magdeburg hemispheres are a pair of large, hollow, metal hemispheres that can be put together to create a vacuum chamber. They were invented by Otto von Guericke in the 17th century and are used to demonstrate the principle of atmospheric pressure.

## 2. How do Magdeburg hemispheres demonstrate action and reaction?

When the two hemispheres are placed together and the air is pumped out, the pressure inside becomes much lower than the atmospheric pressure outside. This creates a vacuum, causing the hemispheres to be held together with a great force. This force is the result of the atmospheric pressure outside pushing in, creating a reaction to the action of removing the air from inside.

## 3. What is the significance of the Magdeburg hemispheres in science?

The Magdeburg hemispheres experiment is an important demonstration of atmospheric pressure and the concept of action and reaction pairs. It also played a crucial role in the development of vacuum technology and understanding of gas laws.

## 4. Can the Magdeburg hemispheres be used for any other experiments?

Yes, the Magdeburg hemispheres can be used for various experiments related to atmospheric pressure, such as creating a vacuum to study the behavior of gases or using them to crush objects with the force of atmospheric pressure.

## 5. Are there any modern applications of the Magdeburg hemispheres?

While the Magdeburg hemispheres are no longer commonly used in scientific experiments, the principle of atmospheric pressure demonstrated by them is still relevant in many modern technologies, such as vacuum cleaners, air pumps, and aircraft design.

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