[填空题]
(a) A yo-yo is made of two solid cylindrical diqk0 ;c b7spujoey:x0:sks, m8 ;9) 6dwbk(ujbi)uux:apbi 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 x)8 uk;bi diu)b6wm(apub9j: 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? %