[填空题]
(a) A yo-yo is made of two s bdfs;1ek9-rpk zc.*u olid cd8qi,n x,wgodb gl *3bmz485eylindrical 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 it reaches the en del bgxgb4mqn5,o,*z id88w3d of its 1.0-m-long string, if it is released from rest. $m/s$ (b) What fraction of its kinetic energy is rotational? %