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Homework Help: Questions on momentum and collisions

  1. Dec 2, 2007 #1
    Hey these could be simple questions with easy formulas and just plugging in but i don't have them my teacher is the worst teacher i have ever had in high school and what help i can get is appreciated

    1. The problem statement, all variables and given/known data
    A 68.0 kg ice skater moving to the right with a velocity of 2.99 m/s throws a 0.15 kg snowball to the right with a velocity of 22.7 m/s relative to the ground.

    A second skater initially at rest with a mass of 60.50 kg catches the snowball. What is the velocity of the second skater after catching the snowball in a perfectly inelastic collision?

    An 92.8 kg astronaut is working on the engines of a spaceship that is drifting through space with a constant velocity. The astronaut turns away to look at Earth and several seconds later is 28.7 m behind the ship, at rest relative to the spaceship. The only way to return to the ship without a thruster is to throw a wrench directly away from the ship. If the wrench has a mass of 0.560 kg, and the astronaut throws the wrench with a speed of 18.0 m/s, how long does it take the astronaut to reach the ship?

    2. Relevant equations

    3. The attempt at a solution
    I don't really know where to start but i can figure out the momentum of the skaters
    1) Momentum of skater is= p=mv
    Momentum of Snowball p=mv
    for the Astronaut question i use Pi=Pf but i don't know how to break down the equation but i do something with the momentum of the wrench with distance and i don't know an equation for that
    Last edited: Dec 2, 2007
  2. jcsd
  3. Dec 2, 2007 #2


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  4. Dec 2, 2007 #3
    thanks hage good website Bookmarked it =D
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