[填空题]
(a) A yo-yo is made of two solid cylindrical disks, each of mass 0.v8lc /uqur0up.g* fr: 050 kg and .r4:eucjk5t-z as01c:c r v oxdiameter 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 ta1k tc4xecor5 uv:. js-c rz0:o 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? %