[填空题]
(a) A yo-yo is made of two s9 h.jn *zmhxxs0h5b ;solid cylindrical disks, each of mass 0.050 kg myhw28ja : jzsi.r6up,83yfhand diameter 0.075 m, joined by a (concentric) thin solid cylindrical hub of mass 0.h uwj mf.sz 8 r,6i3yhy8j2:pa0050 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? %