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Homework Help: Balanced and unbalanced forces

  1. Nov 26, 2012 #1
    The following forces act on a hockey puck (round, rubber disk) sitting on a frictionless surface: F_1 = 15.5 N at 15 degrees; F_2 = 27.9 N at 125 degrees; and F_3 = 31.7 N at 235 degrees. All the forces are in the plane of the ice. Determine the net force on the puck.

    Fnetx= F1x-F2x-F3x=max, Fnety= F1y+F2y-F3y=may

    F2x=27.9Ncos125= -16
    F3y=31.7Nsin235= -25.96


    Im getting this problem wrong and I am not sure where I am messing up.
  2. jcsd
  3. Nov 26, 2012 #2

    Doc Al

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    Staff: Mentor

    Don't ignore the signs of the components when you add them up.
  4. Nov 26, 2012 #3


    Staff: Mentor

    You should simply sum the forces with the values you've computed for the x and y components:

    Fnetx = F1x + F2x + F3x and similarly for Fnety