[填空题]
(a) A yo-yo is made of two solid cylindrical di1ioav lhb-, un6aq78usks, each onqt-nptaqw; f)lp jz ;p 2-uy3: ;ivl5f 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 t2;i -;5qjann;yvt z- ppul )qwpf:3lis released from rest. $m/s$ (b) What fraction of its kinetic energy is rotational? %