[填空题]
(a) A yo-yo is made of two solid cyl 3rj8, xhzqek ;d0k)a/gsmbc+indrical disks, each of massl n(tym* sk,(n 0.050 kg and diameter 0.075 m, joined by a (concentric) thin solid cylindrical hub of mass 0.0050 kg and diameter 0.*,sn(mnt y(lk 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 it is released from rest. $m/s$ (b) What fraction of its kinetic energy is rotational? %