Homework Help: Angular momentum problem (ball sticking to one end of a see saw)

1. The problem statement, all variables and given/known data

A 4.80 ball is dropped from a height of 15.0 above one end of a uniform bar that pivots at its center. The bar has mass 7.00 and is 8.60 in length. At the other end of the bar sits another 5.40 ball, unattached to the bar. The dropped ball sticks to the bar after the collision.

2. Relevant equations



3. The attempt at a solution
my attempt at doing this was to conserve angular momentum. so it is initially mvr where r is half of the length of the rod and v is the velocity found by equating kinetic energy with potential energy. then i set this equal to Iw of the final system but i dont know how to find I of this. I figured once i had I i could find w and set v of ball to wr and then use conservation of energy again to find the hight the ball rose.