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Do I need to consider normal force when sliding down a pole

  1. Oct 31, 2017 #1
    If someone was sliding down a vertical pole (like a firefighter) would only friction need to be considered to find out how fast the person is "falling" or is there also normal force from where the person is touching the pole, and would that affect the person's speed down?
    (I am ignoring air resistance)
     
  2. jcsd
  3. Oct 31, 2017 #2

    mfb

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    Do you expect the person to accelerate away from the pole?
     
  4. Oct 31, 2017 #3
    sliding down the pole
     
  5. Oct 31, 2017 #4
    No, the person is sliding down a pole, my question kind of has to do with newton 3rd law that says when an object exerts a force on a 2nd object, that 2nd object will exert an equal and opposite force on the 1st object .I am asking a few things:
    1) if someone is sliding down a vertical pole is he or she exerting a force on the pole since the person is basically in free fall?
    2) if they are exerting a force, then the pole has a normal force too right?
    3) if there is a normal force do will it affect how fast the "sliding person" is going down?
     
  6. Oct 31, 2017 #5

    mfb

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    If the person would be in free fall, they wouldn't need the pole. Typically you slow down your motion with the pole, which means you are not in free fall. The relevant force is purely vertically, however.
     
  7. Oct 31, 2017 #6

    I like Serena

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    If you put a firmer grip on the pole, the pole will push back with a greater normal force.
    Consequently the friction is greater, slowing you down.
     
  8. Oct 31, 2017 #7

    NascentOxygen

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    True, but the pole is firmly secured to withstand unbalanced forces. If you were to investigate slowing your descent by pushing against only one side of the pole, expect to find yourself rapidly moving farther and farther from the pole during your travel..
     
  9. Oct 31, 2017 #8

    jbriggs444

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    The pole is typically round. Depending on where you push on it, the "normal force" can be in any direction you choose. If you wrap your forearms, body and legs around it (never slide down using your hands -- prescription for burns), the normal forces in every direction cancel with each other and you are left with nothing but friction.
     
  10. Oct 31, 2017 #9
    Okay I understand it now . Thank you.
     
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