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Kinetic Energy Ping Pong ball Question

  1. Jun 4, 2008 #1
    [SOLVED] Kinetic Energy Question

    1. The problem statement, all variables and given/known data
    A 7.0 kg bowling ball moves at 2.35 m/s. How fast must a 2.40 g Ping-Pong ball move so that the two balls have the same kinetic energy?

    m1= 7.0kg
    v1= 2.35m/s
    m2= .0024kg
    v2=?


    2. Relevant equations

    I know that:
    KE= 1/2mv^2

    3. The attempt at a solution
    I set my equation like so:
    KE1=KE2

    and I reduced it to this:
    m1v1=m2v2

    I plugged in the values and solved for v2:
    (7.0kg)(2.35m/s)=v2 (.0024kg)
    v2= 6854.17

    I put this answer in and it tells me...
    wrong check mark
    Your answer differs from the correct answer by orders of magnitude. m/s


    What am I doing wrong? Please point me in the right direction.
     
    Last edited: Jun 4, 2008
  2. jcsd
  3. Jun 4, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Good.

    Good.

    You made an error here. The kinetic energy equation doesn't reduce to this.

    (Don't leave off squaring the speeds.)
     
  4. Jun 4, 2008 #3
    Thank you Doc Al.

    The correct answer was 127m/s
     
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