[填空题]
(a) A yo-yo is made op;b3neheew t :88w3qlx6ddt 5f two solid cylindrical disks, each of mass 05u dd8*k kh7ey.v7cseuo8v 4b.050 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, ifh d cb7eysuv*kd4.u5e88vk 7o it is released from rest. $m/s$ (b) What fraction of its kinetic energy is rotational? %