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Homework Help: Mechanics problem

  1. Dec 6, 2009 #1
    1. The problem statement, all variables and given/known data
    An athlete running with a constant speed jumps and lands 1 second later 5 meters from the point where she jumped. How fast was she running? How high did she jump?

    2. Relevant equations
    v=u+at, d=ut+1/2at^2

    3. The attempt at a solution
    I have no idea how to get started but the answers are 5 and 1.25 respectively.
  2. jcsd
  3. Dec 6, 2009 #2


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    Once airborne, the athlete may be treated as a projectile. Use the two well-known facts about projectile motion

    1. The vertical component of the initial velocity is related to maximum height and the time of flight.
    2. The horizontal component of the initial velocity does not change.

    Assume that when the athlete "jumps", she gives herself a push in the vertical direction only, i.e. she changes only the vertical component of her velocity from zero to something other than zero.
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