[填空题]
(a) A yo-yo is made of two solid cylindrical disks, each of mass 0t80 bsszg;0;jkz a q;jq;am 6ar3bq0i .05 fw kgb/u3:6bwj* opl80 kg and diameter 0.075 m, joined by a (concentric) thin solid cylindrical hub of mass 0.0050 kg and diameter 0.010 m. Use conservation of energy to calculate the linear speed of the yo-yo when it reaches the end of its 1.0-m-long string, if itob bfgw8 j /6u3p:*klw is released from rest. $m/s$ (b) What fraction of its kinetic energy is rotational? %