A chain of metal links with total mass M = 7 kg is coiled up in a tight ball on a low-friction table (Figure 9.49). You pull on
a link at one end of the chain with a constant force F = 50 N. Eventually the chain straightens out to its full length L = 2.6
m, and you keep pulling until you have pulled your end of the chain a total distance d = 4.5 m.
(a) Consider the point particle system. What is the speed of the chain at this instant?
(b) Consider the real system. What is the change in energy of the chain?
(c) In straightening out, the links of the chain bang against each other, and their temperature rises. Assume that the
process is so fast that there is insufficient time for significant transfer of energy from the chain to the table due to the
temperature difference, and ignore the small amount of energy radiated away as sound produced in the collisions
among the links. Calculate the increase in internal energy of the chain.