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Homework Help: Firework exploding

  1. Feb 27, 2008 #1
    1. The problem statement, all variables and given/known data

    A firecracker is tossed straight up into the air. It explodes into three pieces of equal mass just as it reaches the highest point. Two pieces move off at 130 m/s at right angles to each other. How fast is the third piece moving?

    2. Relevant equations

    3. The attempt at a solution

    I'm not sure what to do with this problem, I thought the third piece would be the same as the other two at 130m/s but this is not the case. What is there to do?
  2. jcsd
  3. Feb 27, 2008 #2
    Conservation of momentum

    Initially the momentum is zero(because it was at the highest point and wasn't moving)

    but now you have three pieces, so the x and y components of the three pieces' momentums(I hate saying momenta)must cancel so that Pi=Pf
  4. Feb 27, 2008 #3
    so does Pi = 260(mass) and Pf = mass(velocity) so the masses cancel and the velocity is 260?
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