let r be the radius and m is the mass then the moment of inertia
of a solid sphere is  I = 2mr2 / 5
1 = 2/5 * ( 6.93 *
r2)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
1 pound = 0. 45 kg
r = 0.6 m
                                                                       Â
15.4 pounds = 6.93 kg
therefore the diameter should be d=2r = 1.2
m
