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F=ma problem

  1. Sep 28, 2005 #1
    1) A 75 kg man falls 3.10 meters to the ground. He moves an additional 0.6 meters as his knees bend when he hits the ground.
    a) what is his speed as his speed when his feet touch the ground? - I solved this as 7.79487 m/s
    b) What is his acceleration as he slows down if acceleration is assumed to be a constant? How do i get this?
    c) What is the net force on the man and what is the average force his feet exert on the ground as he slows?
  2. jcsd
  3. Sep 28, 2005 #2


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    Hint: use the basic equation of motion:

    [tex]x = v_0t + \frac{1}{2} at^2[/tex]

    and think of it as two separate problems.
    Last edited: Sep 28, 2005
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