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Momentum/KE Problem

  1. Mar 31, 2008 #1
    A neutron with a mass of 1.67×10^−27 kg and moving with a speed of 45000 m/s makes a head-on collision with a boron nucleus with a mass of 1.66×10^−26 kg. The boron nucleus is originally at rest.

    If the collision is perfectly elastic, what fraction of the neutron's original kinetic energy is transferred to the boron nucleus?
     
    Last edited: Mar 31, 2008
  2. jcsd
  3. Mar 31, 2008 #2

    berkeman

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    What equations apply? You need to show your work before we can offer tutorial help.
     
  4. Mar 31, 2008 #3
    I used the conservation of momentum equation, M neutron * Vi,n = M neutron * Vf,n + M boron * Vf,b

    Then I would use the KE equation .5(M neutron)(Vi,n)^2 = .5(M neutron)(Vf,n)^2 + .5(M boron)(Vf,b)^2

    However, I realized that I would be messing with two unknowns and I have no idea how to approach that, unless I'm totally off with the equations I presented.
     
  5. Mar 31, 2008 #4

    Hootenanny

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    You indeed have two unknowns, but you also have two equations, which you can solve simultaneously.
     
  6. Mar 31, 2008 #5
    Ah... Ok, I guess I have to do some kind of substitution.
     
  7. Mar 31, 2008 #6

    Hootenanny

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    That would be the way forward... :smile:
     
  8. Mar 31, 2008 #7
    Oh no... Looks like I have to use the quadratic formula for this... -.-'
     
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