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Homework Help: Calculate a diver's turns in air

  1. Nov 15, 2009 #1
    1. The problem statement, all variables and given/known data
    The rotational inertia for a diver in a pike position is about 15.5 kg m2; it is only 8.0 kg m2 in a tucked position (the figure above).

    (a) If the diver gives himself an initial angular momentum of 106 kg m2/s as he jumps off the board, how many turns can he make when jumping off a 10.0-m platform in a tuck position? [Hint: Gravity exerts no torque on the person as he falls; assume he is rotating throughout the 10.0 m dive.]

    (b) How many in a pike position?


    2. Relevant equations

    WiIi= WfIf
    n= (wf/2Pie) t

    3. The attempt at a solution

    The teacher mildly went over this problem in class. These are the eqns he gave us. I tried to solve for wf and substituted that answer in the second eqn to find the number of turns in time t, which i calculated thru the eqn :
    h=vit + 1/2 at2
    I really have NO idea how to do this problem, i only know these eqns from wat the instructor provided. If you can please teach me how to go about solving the problem and understanding it, i would really truly appreciate it!! Thanks!

    Attached Files:

  2. jcsd
  3. Nov 15, 2009 #2


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    Homework Helper

    Don't you just need angular momentum = I*ω to find ω?
    After that, use your second formula to get the number of turns in the time it takes to fall to the water.
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