Calculate a diver's turns in air

[agadag]

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

W_iI_i= W_fI_f
n= (w_f/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 w_f and substituted that answer in the second eqn to find the number of turns in time t, which i calculated thru the eqn :
h=v_it + 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!

 

[Delphi51]

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.