[填空题]
(a) A yo-yo is made of two solid cylindrical disks, each of mz :vrf6,zlj h*a ll*7ez4inmgo p5x:t7l3:f z*erv zo *ss 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 sp f prxl3miz*z l74l:5g *o: zn*oe7etveed 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? %