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Homework Help: Can someone help me with solving this problem? Kinematics

  1. Oct 22, 2012 #1
    1. The problem statement, all variables and given/known data

    In a 1985 study, cats were trained to jump up and touch a cotton ball in an effort to study their thigh muscles. One cat was able to jump 2.93 meters off the ground.

    What is its hang time? In other words, what total time was the cat in the air?
    What was its initial velocity?
    What was its final velocity?

    Vi and Vf do not equal 0
    A = -9.8
    D = 2.93 or 5.86
    How does this make any sense? Don't I only have two variables (acceleration and displacement) and I need at least three to solve all of the kinematics?

    2. Relevant equations


    3. The attempt at a solution

    I've used plenty of different equations and can't seem to find anything out.
  2. jcsd
  3. Oct 22, 2012 #2
    Think of its jump as two events: the cat jumps up, the cat falls down. What is its velocity at before and after each event?
  4. Oct 22, 2012 #3
    Hint: you're not gonna be able to answer your questions in order...
  5. Oct 22, 2012 #4


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    Homework Helper

    You know the maximum height the cat has reached - 2.93 m. If it had still some speed at that height it would have risen higher. So you have vf=0 when the displacement is 2.93 m. You can also find the time. Falling back takes the same time.

  6. Oct 23, 2012 #5
    This is a great site for 1 Dimensional Kinematics problems on up, it also shows step by step solutions to problems like this and many more: http://www.physicsclassroom.com/
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