[填空题]
(a) A yo-yo is made of two solidae l-0: ap sv4hzw8w0w cylindviaikjub)( q 00 * tir 5iu,.k/hz:jsurical 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 cosrqzijiikjt.0uk(b: )* u5 i0h, avu/ nservation 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? %