help, Physics problem, conservation of angular momentum?

[adamstgg]

A child of mass 45.3 kg sits on the edge of
a merry-go-round with radius 1.4 m and moment of inertia 67.4789 kg m2. The merry-go-round rotates with an angular velocity of 2.9 rad/s.

1)What radial force does the child have to
exert to stay on the merry-go-round? in N.

2)The child then walks towards the center of
the merry-go-round and stops at a distance
0.518 m from the center. Now what is the angular
velocity of the merry-go-round? in rad/s.