[问答题]
A large spool of rope u) /qw0f8b i/9e kihtyrolhompn7;nbb /4ls on the ground with the end of the rope lying on the top edge of the spool. A person grabs the end of the rope and walks a distance L, holding onto it, Fig. 8–50. The spool rolls behind the person without sn47bp m/oh nb;lipping. What length of rope unwinds from the spool? How far does the spool’s center of mass move?