1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook