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Homework Help: Find the mass of the skateboard

  1. Dec 3, 2008 #1
    1. The problem statement, all variables and given/known data
    A 43.9 kg student runs down the sidewalk and jumps with a horizontal speed of 4.03 m/s onto a stationary skateboard. The student and skateboard move down the sidewalk with a speed of 3.85 m/s.
    a) find the mass of the skateboard. answer in units of kg
    b) How fast would the student have to jump to have a final speed of 6.93 m/s. Answer in units of m/s.

    I assume I would need to find how fast he runs down the sidewalk to begin? Would I then add that to the horizontal speed, or would I have to add them like vectors...?
  2. jcsd
  3. Dec 3, 2008 #2


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    Science Advisor
    Homework Helper

    Re: collision

    How would you figure that out? I don't think you can. Just assume the students speed when landing on the skateboard is 4.03m/s and use conservation of momentum.
  4. Dec 3, 2008 #3
    Re: collision

    i see. Thank you for your help! :)
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