Water Pressure & World Rotation: An Unanswered Query

In summary, the question asks why shooting water at a wall with a hose does not have an effect on the world's rotation. The answer is that the Earth's momentum is extremely large compared to the momentum of the water, making the force between the two negligible. This is due to the principle that for every action, there is an equal and opposite reaction, resulting in no net force on the wall. This can be compared to the idea of using a fan to make a sailboat sail without wind.
  • #1
StephenP91
14
0

Homework Statement


A wall is firmly in the ground, if you shoot water at it via a hose why does it not have an effect on the world's rotation?


Homework Equations





The Attempt at a Solution



The question is something like that. You get the general idea.
 
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  • #2
well, think about the relative sizes of the force between the water hitting the wall, and the rotation of the earth.

There's a hint.
 
  • #3
Char. Limit said:
well, think about the relative sizes of the force between the water hitting the wall, and the rotation of the earth.

There's a hint.

No, I'm not getting it, ultimately the question is asking for some reference to momentum.
 
  • #4
StephenP91 said:
No, I'm not getting it, ultimately the question is asking for some reference to momentum.

Well, yes. The Earth's momentum depends on its mass, an extremely large number, and its velocity, another rather large momentum. In contrast, the momentum of the water is negligible by comparison.
 
  • #5
Char. Limit said:
Well, yes. The Earth's momentum depends on its mass, an extremely large number, and its velocity, another rather large momentum. In contrast, the momentum of the water is negligible by comparison.

I read it as no effect. :uhh: Ahh well, thank you.
 
  • #6
This is more a physics problem than a mathematics problem.

It is true that the Earth's mass (and so momentum) is very large compared to that of the water but, in fact, there is exactly 0 net force on the earth- the size of the Earth is irrelevant.

"For every action, there is an equal and opposite reaction".

In order to spray water on the wall, you have to hold the hose that is spraying the water. As the water leaves the hose, it is exerting as much force on you as it will on the wall. And, of course, your feet braced on the Earth prevent you from moving backwards just as the wall's hold on the Earth prevents it from moving. Both you and the wall are exerting the same force on the Earth but in opposite directions. There is no net force on the wall.

This is similar to the suggestion that you can make a sailboat sail without wind by putting a powerful fan, aimed at the sail, in the stern of the boat!
 

1. What is the relationship between water pressure and the rotation of the Earth?

The relationship between water pressure and the rotation of the Earth is complex and not fully understood. However, it is believed that the rotation of the Earth creates a centrifugal force that affects the distribution of water on the planet's surface, resulting in variations in water pressure.

2. Does water pressure vary depending on the Earth's rotation?

Yes, water pressure can vary depending on the Earth's rotation. The rotation of the Earth creates a centrifugal force that affects the distribution of water on the planet's surface, resulting in variations in water pressure.

3. How does the Earth's rotation impact ocean currents and water pressure?

The Earth's rotation plays a significant role in the formation and movement of ocean currents, which in turn can affect water pressure. The Coriolis effect, caused by the Earth's rotation, influences the direction of ocean currents and can also impact water pressure.

4. Are there any studies or theories that explain the correlation between water pressure and the Earth's rotation?

There have been several studies and theories proposed to explain the correlation between water pressure and the Earth's rotation. Some suggest that the rotation of the Earth creates a centrifugal force that affects the distribution of water, while others propose that the Coriolis effect plays a role in ocean currents and water pressure.

5. Can variations in water pressure caused by the Earth's rotation have any significant impact on the planet?

While the exact impact of variations in water pressure caused by the Earth's rotation is not fully understood, it is believed that it can play a role in ocean circulation and climate patterns. However, other factors such as wind and temperature also have significant influences on these systems.

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