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Homework Help: Coefficient of restitution problem

  1. Jun 26, 2011 #1
    1. The problem statement, all variables and given/known data

    The two identical steel balls A and B moving with initial velocities VA = 6 m/s and VB = 8 m/s collide, as shown in figure Q4. If the coefficient of restitution is e = 0.7, determine the magnitude and direction of the velocity of each ball just after impact.
    (See Attachment, Question 4)

    3. The attempt at a solution

    Calculate the y-component of VA.
    VA(y) = 6*cos(30) = -5.196 m/s (Since it is travelling in the -y direction)

    e = (VB' - VA')/(VA - VB)


    (VB' - VA') is the relative velocity of separation after impact (m/s)
    (VA - VB) is the relative velocity of approach (m/s)
    e is the coefficient of restitution

    0.7 = (VB' - VA')/(-5.196 - 8)

    0.7*(-5.196 - 8) = (VB' - VA')

    -9.2372 = (VB' - VA')

    Is this method correct so far? If so, I don't know where to go from here.

    Attached Files:

  2. jcsd
  3. Jun 27, 2011 #2
    Any help on this question would be great as I got this same question on an exam and I am wondering if I got the beginning right or not.
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