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Rod and we pull one end of it with a 10N force

  1. May 30, 2005 #1
    an example problem statement
    there is a rod and we pull one end of it with a 10N force with the other end fixed.

    recall that a force acts on a body only when it accelerates. But in the above problem is it correct to say that 10N force is applied (i see
    that there is no force applied on it since there is no acceleration of the rod)
  2. jcsd
  3. May 30, 2005 #2
    If the other end is fixed, then it will apply a normal force of magnitude 10N to whatever it is fixed to. It's net force is zero.
  4. May 30, 2005 #3
    This isnt true. A NET force acts on a body if it accelerates. Or more properly, an object will accelerate only if it has a net force acting on it.
  5. May 30, 2005 #4


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    There is no net force. Because there are forces, acting in opposite directions at the ends of the rod, there is tension in the rod.
  6. May 30, 2005 #5
    On earth a stationary book on a tabletop (in a vacuum blah blah blah) is still being pulled down by a force, namely gravity but that is balanced by the normal force of the table pushing up on the book. So there are no net forces, like the others have said, but there are forces. Forces are ubiquitous and invisible.
  7. May 30, 2005 #6


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    Nope.Gravity determines a pressure force by the book acting on the table.The reaction force is its pair in the spirit of Newton's III-rd principle.

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