Physics Problem?

Question

A flat uniform circular disk (radius = 5.56 m, mass = 140 kg) is initially stationary. The disk is free to rotate in the horizontal plane about a frictionless axis perpendicular to the center of the disk. A 49.0-kg person, standing 1.46 m from the axis, begins to run on the disk in a circular path and has a tangential speed of 2.00 m/s relative to the ground. Find the resulting angular speed (in rad/s) of the disk.

No picture provided

Answer 1

Angular momentum will be conserved
angular momentum=I*w

for the runner
I=49*1.46^2

For the disk
I=140*5.56^/2

therefore
0=49*1.46^2*2/1.46-
w*140*5.56^2/2

solve for w
w=0.066 rad/s

j