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I need help

  1. Nov 4, 2006 #1
    I need to prove that the distance of an object launched by a rubber band decreases as its mass increases, algebratically. Can anyone help me? Thanks.
  2. jcsd
  3. Nov 4, 2006 #2
    Treat the rubber band as a spring that obeys Hooke's Law (F=-kx). If you displace the rubber band from equilibrium by the same amount for each mass, then the force you apply will be constant. From Newton's 2nd Law, if your force is constant, acceleration is inversely proportional to mass. Then it becomes a kinematics problem.
  4. Nov 4, 2006 #3
    Can you explain that further? I'm not quite getting it.
  5. Nov 4, 2006 #4


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    Homework Helper

    JohnnyA42 wanted to point this out: from Newton's 2nd law you have F / a = m. Since F is constant, if you increase m, a must decrease.
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