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Homework Help: Perfectly Inelastic and initial kinetic energy

  1. Jan 26, 2009 #1
    An object of mass m (O1) moving with speed v collides head-on with a target object of mass 2m (O2) initially at rest. If the collision is perfectly inelastic, what fraction of O1's initial kinetic energy is lost?





    1/2(m1)v^2=1/2(m1+m2)(1/3*v)^2 .... is this right so far?
  2. jcsd
  3. Jan 26, 2009 #2
    Take the ratio of the final kinetic energy to the initial kinetic energy. These two are not equal to each other unless you include a ratio factor on the left side of the equation.
  4. Jan 27, 2009 #3
    1/3? 3m*(1/9)v^2 yields a factor of 1/3.
  5. Jan 27, 2009 #4
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