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Newton's Cradle

  1. Jul 30, 2009 #1
    I have asserted that Newton's Cradle does not demonstrate specifically that P = mv or that E = 1/2mv^2.

    Rather, that it demonstrates only that two *different* laws of motion/conservation are simultaneously at work.

    An alternative form of this assertion is that by observing Newton's cradle, you cannot *specifically* derive the above two equations, but rather only an infinite number of pairs of *consistent* equations.



  2. jcsd
  3. Jul 30, 2009 #2
    Those are mathematical formulations of the definitions of momentum and KE, therefore you don't have to "demonstrate" them.In the case of KE the formula can be derived from other definitions but in the end is still a definition.in the case of momentum p=mv and that is that.
    I always considered it a cool toy that shows the conservation laws.
    What pairs of equations are you refering to?
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