[填空题]
(a) A yo-yo is made of two solx92px)h ut.t3*a xefa ide qr t3qj4h9;ak .wy( .s6xhuk cylindrical disks, each of mass 0.050 kg and diameter 0.075 m, joined by a (concentric) thin solid cylindricalqtj h;w3sqa(h..4 ry96xekuk 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 it is released from rest. $m/s$ (b) What fraction of its kinetic energy is rotational? %