Calculate a diver's turns in air

  • Thread starter agadag
  • Start date
  • #1
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Homework Statement


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.]

3.0
4.0
2.0
5.0
4.5
(b) How many in a pike position?

1.2
1.8
1.6
1.1
1.4





Homework Equations



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

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!
 

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Answers and Replies

  • #2
Delphi51
Homework Helper
3,407
11
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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