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Ramp Questiosn

  1. Oct 13, 2005 #1
    im always confued about negative and positive signs, soemone give em a easy way to remember
    is whatever is on the left side of the x-axis egative, and above positive always?
    also when is friction negative, if the mass if moving up a ramp, is friction always negative, and if its moving down, its postitive?
  2. jcsd
  3. Oct 13, 2005 #2
    Friction always action in the opposite direction of the applied force. coordinate system is arbitary you can define positive or negative any way you want.
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