[填空题]
(a) A yo-yo is made of v5wd gm2o*axnlrrhi (9ot5lp z19h3 3two solid cylindrical disks, eaclsd iv1-)l; uoh of mass 0.050 kg and diameter 0.075 m, joined by a (concentric) thin so ;1ls)duivl-olid 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? %