Action reaction force quick question

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SUMMARY

The discussion centers on the action-reaction forces involved when a firewoman opens a fire hose, specifically identifying the forces at play. The action force is the water pushing forward, while the reaction force is the air pushing back against the water. In a vacuum, the absence of air does not negate the existence of action-reaction pairs; the firewoman's force on the hose and the hose's force on the water still apply. The ambiguity of the question is acknowledged, but the fundamental principles of Newton's Third Law are upheld.

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  • Understanding of Newton's Third Law of Motion
  • Basic knowledge of action-reaction force pairs
  • Familiarity with fluid dynamics principles
  • Concept of forces in different environments, including vacuums
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Adam17
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Homework Statement

A firewoman opens the fire hose, and water sprays forward. What is the action force and reaction force?



Homework Equations

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The Attempt at a Solution


I was thinking that the action force would be water pushing on air and reaction air pushing on water? But how would this be possible in space where there is a vacuum?
 
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I think the question is rather ambiguous. The firewoman exerts a force on the hose to hold it at rest. There will be a corresponding reaction force. Can you describe this reaction force?

Also, the hose will exert a force on the water. What is the reaction force to this?

As you stated, the water will exert a force on the air as it moves through the air. And you correctly stated that the reaction force would be the air exerting a force on the water.

[By the way, when dealing with action-reaction pairs, it doesn't matter which of the two forces you call the "action" force and which the "reaction" force.]

If the hose and firewoman are in a vacuum, then of course there would be no force of the water on any air. But you would still have the other action-reaction pairs mentioned above.
 

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