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Homework Help: Magnitude of change in linear momentum

  1. Mar 26, 2008 #1
    1. The problem statement, all variables and given/known data

    A 0.70 kg ball is moving horizontally with speed of 9.6 m/s when it strikes a vertical wall. The ball rebounds with speed of 1.3 m/s. What is the magnitude of the change in linear momentum of the ball?


    2. Relevant equations

    Dp = mv(f) - mv(i)

    3. The attempt at a solution

    I solved for mv(f) and mv(i). Solved for Dp which I got -5.81 which is wrong.
     
  2. jcsd
  3. Mar 26, 2008 #2

    Doc Al

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    Staff: Mentor

    Hint: The initial and final velocities point in opposite directions.
     
  4. Mar 26, 2008 #3
    -.91 - 6.72 = -7.63

    Is the answer positive because magnitude is positive?
     
  5. Mar 26, 2008 #4

    Doc Al

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    Staff: Mentor

    That is correct.
     
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