[问答题]
A large spool of rope rolls on the gromuhk8hzokh .o gy;g* am8j-+: und with the end 7 p,t c-jawx)wu9p z3hof 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 slipping. What length of rope unwinds from the s -cx tpw3wu7ajz,p)9h pool? How far does the spool’s center of mass move?