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Force and Acceleration

  1. Sep 7, 2010 #1
    In class today, my professor said that you will never find a force that is a function of acceleration.

    Why is this?


    M[tex]\ddot{x}[/tex](t) = F(x,y,z,[tex]\dot{x},\dot{y},\dot{z}[/tex],t)
    M[tex]\ddot{y}[/tex](t) = F(x,y,z,[tex]\dot{x},\dot{y},\dot{z}[/tex],t)
    M[tex]\ddot{z}[/tex](t) = F(x,y,z,[tex]\dot{x},\dot{y},\dot{z}[/tex],t)

    This is in a classical mechanics / dynamics course
     
  2. jcsd
  3. Sep 9, 2010 #2

    rock.freak667

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    Usually forces vary with time, because acceleration would vary with time. I think he meant that you would not find a function such that F=2a2+a+3 as that would not work dimensionally.
     
  4. Sep 9, 2010 #3

    rcgldr

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    What about a reaction force? For example a string attached to a ball and accelerating the ball, the force the ball exerts on the string is a function of the acceleration of the ball.
     
  5. Sep 9, 2010 #4

    rock.freak667

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    Well that is what I am saying, I think your professor meant that you would not usually measure force with acceleration or well plot force against acceleration.
     
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