[填空题]
(a) A yo-yo is made of two a6t5kuhc9x*00 9 gl0xjlswfsyf2+ oi solid cylind clc h0g0 *09hbsgy0dh ibhu7(rical disks, each of mass 0.050 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, b0lh h7g 0hig d9cyc0ub(0h*sif it is released from rest. $m/s$ (b) What fraction of its kinetic energy is rotational? %