[填空题]
(a) A yo-yo is made of yit;p/;orn n8d+s ( qutwo solidp5fxv-ov y. s9 cylindrical 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 i-y5 xsv vf9.opt 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? %