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Homework Help: Elastic Glancing Collision-HELP

  1. Aug 8, 2008 #1
    Elastic Glancing Collision-HELP!!!!!!!!

    A white ball, mass of 1 kg has a speed of 1.68 m/s and a yellow ball, mass of 2kg, is at rest prior to an elastic glancing collision. After the collision the white ball has a speed of 1.24 m/s. To the nearest tenth of a degree, measured counterclockwise from east, what angle does it scatter at if the yellow ball is scattered at 280degrees?

    I don't know what equations to use for this problem!
  2. jcsd
  3. Aug 8, 2008 #2
    Re: Elastic Glancing Collision-HELP!!!!!!!!

    I used this equation:

    1/2mv_1i^2 = 1/2mv_1f^2 + 1/2mv_2f^2 (the 1i, 1f, and 2f are subscripts indicating which velocities)

    When I plugged in the numbers from the problem, I got that the final velocity for the yellow ball is 0.801m/s.

    I then used the following equation:


    But sin becomes greater than 1, so it's a domain error.

    Am I doing something completely wrong?
    Or is it possible that for this problem to work, the mass of the white ball must be greater than that of the yellow ball?
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