[填空题]
(a) A yo-yo is made of two solid cylindrical diskm/ i2azd*yn)ihuvt8 gve)+8b s.)f em euy53sz, each of mass 0.050 kg and diametee)fem5 .3uszyr 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, if it is released from rest. $m/s$ (b) What fraction of its kinetic energy is rotational? %