[填空题]
(a) A yo-yo is made of two sol1 wlne4*r 2daa(nw wx)id cylindrical disks, each ou1npkr9u6wl 0ck: t n:f 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 end of its 1.0-m-long string, if it is release 0 n1t6r9ukcn::uklpwd from rest. $m/s$
(b) What fraction of its kinetic energy is rotational? %