[填空题]
(a) A yo-yo is made of two solu5.c;.ldscj3h6 si mg,m5gpdid rtnm9medg),:).z w-lj;xw j acylindrical 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 reaj :laj ;e-tm x.r) mz)nw,9gdwches 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? %