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Homework Help: Conservation law of mometum

  1. Nov 28, 2015 #1
    1. The problem statement, all variables and given/known data
    In a pairs skating competition, the male skater is initially carrying his partner. Together they have a mass of 130.0 kg and they are are moving forward with a velocity of 2.5 m/s. If the male skater throws his partner forward at 1.5m/s, find the velocity of the male skater after he throws his 45.0kg partner.

    2. Relevant equations
    Pa + Pb = P'a + P'b

    v= p/m

    3. The attempt at a solution
    So assuming the equation to find velocity which is v=p/m all i have right now is the mass of the male skater which is 85kg. Now im not to sure what to do with the original combined momentum ( both skaters together) which was p= (130kg)(2.50m/s)= 325kg.m/s...... Now would what do i do with that do find the answer?
  2. jcsd
  3. Nov 28, 2015 #2


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    Staff: Mentor

    You know it is conserved, you can apply that to find a condition on the final velocities. The other condition is given in the problem statement.
  4. Nov 28, 2015 #3


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    Staff: Mentor

    You have more than just the mass of the male skater. You have the total momentum, and you have the mass and velocity of the thrown skater (assuming the thrown velocity is with respect to the ice rink and not the male skater).
  5. Nov 28, 2015 #4


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    Gold Member

    Considering the numbers given, that would not be my assumption.
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