1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Action reaction force quick question

  1. Jun 16, 2012 #1
    1. The problem statement, all variables and given/known dataA firewoman opens the fire hose, and water sprays forward. What is the action force and reaction force?

    2. Relevant equationsnone

    3. 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?
  2. jcsd
  3. Jun 16, 2012 #2


    User Avatar
    Homework Helper
    Gold Member

    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.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?