1. The angular velocity of the disk is  

          omega(disk)  =    0.0462  rad/sec


2. The angular momemtum of the disk (which has mass M = 5321 kg) is

          L(disk)      =    768  kg*m^2/s


3. Joe's angular momentum around the center of the disk must be 
   equal and opposite:

          L(disk)  +  L(Joe)  =  0

          L(Joe)  =  -L(disk)  =  -768 kg*m^2/s


4. Joe's mass is 60 kg, and his distance from the center of the  
   disk is R = 2.5 meters.  His angular velocity is in the
   direction opposite to that of the disk

                            L(Joe)
          omega(Joe)  =  -----------   =   -2.046 rad/sec
                          m(Joe)*R


5. How fast is Joe moving?  His angular velocity relative to 
   that of the disk is

          omega_diff  =   omega(Joe)  -  omega(disk)

                      =   -2.092  rad/sec

   so the magnitude of the linear speed of his feet, relative to 
   the disk, is

             speed    =  abs(omega_diff*R)  =  5.23 m/s