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Linear Momentum, Impulse, Center of a Mass, Velocity, Kinetic Energy

  1. Nov 23, 2010 #1
    1. The problem statement, all variables and given/known data

    Two ice skaters (m1 = 85kg and m2 = 52kg) in a pairs-skating tournament are both initially holding on to each other while travling to the right at 4.5 m/s. Skater #1 then thows skater #2 to the right in a graceful toss. Immediately afterward, skater #2 is travling to the right at 9 m/s (ignore friction).

    a. What is the final velocity of skater #1? Is it to the right or left?

    b. What was the change in total kinetic energy of the skaters due to the throw? Was net kinetic energy gained or lost?

    c. If the throw took .5s, what was the magnitude of the impulsive force on skater #2?

    d. Was the impulsive force acting on skater #1 was less than, the same as, or greater than the force on skater #2?

    e. Find the final velocity (after the throw) of the center-of-mass of the two skaters.

    2. Relevant equations
    Not sure

    3. The attempt at a solution

    a. I thought skater #1 would be traveling at 2.25 m/s to the right. If he threw skater #2 as to increase her speed by half, then his speed should be reduced by half.

    Didn't understand the rest of the questions.
  2. jcsd
  3. Nov 23, 2010 #2


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    Welcome to PF!

    Hi DMRika! Welcome to PF! :smile:
    No, it doesn't work like that. :redface:

    Use conservation of momentum
    What is the definition of kinetic energy ?
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