8.8 As depicted in Figure 4, a chain of length \(L\)  and mass \(M\) is placed on a table, with \(L/ 2\)  hanging off the edge of the table. At \(L/4\)  from the end of the chain that is on the table, there is a block of mass \(m\) . Given that the coefficient of friction between the block and the chain is \(\mu_{1}\) , and the coefficient of friction between the chain and the table is \(\mu_2\) , and that both the chain and the block slide off the table at the same time, determine the velocities of the block and chain at the moment they leave the table.