[问答题]
A large spool of rope rolls on,2i +v6a dc/ufqxqo0qvok b,- mtt(c: the ,y6wb0cwx qf7ground 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 rolqw0yx cb6f7,w ls behind the person without slipping. What length of rope unwinds from the spool? How far does the spool’s center of mass move?