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Homework Help: Explosion Problem

  1. Nov 18, 2008 #1
    1. The problem statement, all variables and given/known data
    A 3.0 kg mass sliding on a frictionless surface explodes into 3 1.0kg masses. After the explosion the velocities of the three masses are: (1) 9.0 m/s north, (2) 4.0 m/s 30 degrees south of west, and (3) 4.0 m/s south of east. What is the original spped of the 3.0 kg mass?


    2. Relevant equations

    Pi=Pf
    P=mv

    3. The attempt at a solution
    Pi=Pf
    3v= (1)9+ (1)4+(1)4
    I know this is wrong. I am confused about what to use for the magnitude and direction of these velocities. would it be 4tan(3) for both of them?
     
  2. jcsd
  3. Nov 19, 2008 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi ScullyX51! :smile:

    Momentum is a vector, so you must use vector addition, not ordinary addition.

    (since there are four vectors, a vector triangle won't be very much use :rolleyes:, so: ) use x and y coordinates. :smile:
     
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