Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

B Arm-wrestling -- question about forces

  1. Jan 2, 2018 #1
    In the arm-wrestling, when the hand A prevails on the hand B, the force of A on B is greater than that of B on A?
     
  2. jcsd
  3. Jan 2, 2018 #2

    Orodruin

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member
    2017 Award

    No. That would violate Newton's third law. The torque on the arm of B from the force from A is greater than the torque on the arm of B that B is able to generate.
     
  4. Jan 2, 2018 #3

    A.T.

    User Avatar
    Science Advisor

  5. Jan 2, 2018 #4
    OK thanks.

    Therefore the force exerted by the hand A (also of the strongest man in the world) on the hand B, can never exceed (not even a little) the strength that the hand B exerts on the hand A (therefore represents its maximum limit).
     
  6. Jan 2, 2018 #5

    Orodruin

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member
    2017 Award

    “Strength” is not a standard physics concept. Do not confuse it with force, which is.
     
  7. Feb 27, 2018 #6

    CWatters

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member


    I think you need to distinguish between the muscular force and the total force one hand exerts on the other.

    For example.. the force B exerts on A could stay the same even if B gives up and stops pushing. If A keeps pushing with the same force then when B gives up hand B will start accelerating and that will make up for the loss of muscular force B was applying on A.

    In practice hand A won't be able to maintain the same force on B for very long but while it can hand B will exert the same force on A. Eventually he table will get in the way or hand A will be power limited (power = force * velocity and the velocity is increasing).
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted