[问答题]
A large spool of rope rolls on the ground with the end ofi+n*35urwjo0 o vy42 2edrgg t the3 q,wx6w9 74scwyvall aqr7u4 rope lying on the top edge of the spool. A person grabs the end of the rope and walks a distance L, holding onto ital ws7wa,4qrly6 7wv93uqc4 x, Fig. 8–50. The spool rolls behind the person without slipping. What length of rope unwinds from the spool? How far does the spool’s center of mass move?