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I Can different forces cancel themselves?

  1. Oct 26, 2016 #1
    If for say, I had a ''perfect object'' (Only mass with no dimensions) and I put three non-parallel and different pulling forces on the item, would these cancel themselves? After the doing the experiment myself with a non-perfect item, it seemed there was a slight advancement. The addition of the vectors gave me a near 0N force.

    My questions are, is that slight advancement only due to the imprecision of my material and why do the forces cancel even thought they're all different?
  2. jcsd
  3. Oct 26, 2016 #2

    The Buttered Cat

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    Making it even simpler, if you had an object with just one force acting on it, you can apply an equal and opposite force to cancel that force, correct?
  4. Oct 26, 2016 #3


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    Just add the force vectors. You know what a vector is?
  5. Oct 26, 2016 #4
    I already added them, my questions is more towards the why the cancellation happens even thought the forces are different
  6. Oct 26, 2016 #5


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    If the vectors don't cancel, then the forces don't cancel. It's as simple as that. But maybe there is some friction that you haven't taken into account.
  7. Oct 26, 2016 #6
    It's a little hard to understand your problem. The forces can cancel because they are different. If they were identical (in magnitude and direction) they effects will add up and you cannot have cancellation.

    For two forces they should have same magnitude but opposite directions. For three forces you can have many possibilities, many combinations of magnitudes and directions which will give a zero resultant.
  8. Oct 26, 2016 #7


    Staff: Mentor

    If you have three forces that sum to zero then if you lay them out head to tail then you will get a triangle. You can also get four forces to cancel if you lay then head to tail and you get a quadrilateral. Any number of vectors that takes you in a closed loop when laid end to end results in 0 net force.
  9. Oct 26, 2016 #8
    Thanks for you answers, they really helped me make my mind under the concept. I will definitely be using this website more often.
  10. Oct 26, 2016 #9


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    Any time you drive a car at a constant velocity the forces on it sum to zero (aka cancel out).
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