HELP!!!Rotational kinetic energy problem 1. The problem statement, all variables and given/known data A 4.00kg mass and a 3.00kg mass are attached to opposite ends of a thin 42.0cm long horizontal rod. the system is rotating at angular speed omega=5.60rad/s about a vertical axle at the center of the rod. determine a) kinetic energy K of the system, and b) the net force on each mass. c)repeat parts a and b assuming that the axle passes through the center mass of the system. 3. The attempt at a solution a)KE=1/2mv^2 m=4.00kg+3.00kg=7.00kg v=radius*omega=21*5.60=117.6 therefore KE=48404.16J b)Net force=F_t-F_f=F_t-mu*F_n i don't really know how to get mu from this problem. and how do I get acceleration for F_t c)total mass*radius for center mass=m1r1+m2r2=4*21+3*21=147 7*radius of center mass=147 therefore radius of center mass=147/7=21... But it is same as question a and b Can anybody help me with it. Thank you very much.