[填空题]
(a) A yo-yo is made of two solid cibytp gx1729uyx) 4tb/vm,+6y n5s wtm2l pseqlindrical disks, each of mass 0.050 kg and diameter 0.075 m, joined by a (concentric) thin solid cylindrical hub of mass26lm q 5wxmyt4 tp,bes/ vn)s+ 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? %